Broadband speeds

Is there a 'loss' of speed at a pc if other devices are attached to the router?

I have a 'nominal' 48Mb at the connection point, but all speed tests indicate around 34-36 delivered from the router. Connected is a wireless net (Billion router in use) and a Gigaset A580 VOIP router also plugged in to the Billion.

Question thus is will the wireless net AND the VOIP be reducing my speed even when they are 'idle' - ie no actual wireless traffic or calls in/out?

ISP have had BT re-route me due to a 'hot' exchange which did improve speed but still maxing at 34-36.

Is your connection wired?

Can you run a speedtest from this site and link to the results and a copy of your modem stats may be useful.

You VOIP router does still have some traffic - albeit very, very low when not in use, but no where near enough to make a noticeable impact on speeds.

Thanks, MHC. Speedtest concerned are cabled direct into router. Not sure which stats you want?

Does a wif-fi network pull down speeds at idle ? What sort of drain would the VOIP be causing?

The only things which will pull down speeds are those which are using WAN/Internet connectivity.

VOIP will normally have keep alives - measurably in ten of bits per second (average). There will be an occasional - "I am here" type message to maintain registration.

A WiFi network will not - unless you are providing a BT WiFi hotspot when there could be occasional traffic or a roaming user.


Speedtest from http://www.thinkbroadband.com/speedtest.html

Modem stats: Sync Speed, Max Attainable Speed, attenuations and SNR.

This speedtest is via a Homeplug but is pretty similar to the results of a direct wiring to the router.
Test

Sync Speed 48998
Max Attainable Speed Varies - around 54-58
Attenuations 20.4 down 0 up
SNR. 7.6 down 6.1 up

Edited by mikejp (Sat 02-Jul-16 11:38:40)

Plusnet, eh?

Two things spring to mind...
a) Are you being limited by the wrong setting on Plusnet's "current line speed"? This value has been known to get stuck

http://forums.thinkbroadband.com/plusnet/t/4478906-r...

b) What package are you on? That result could happen if you are on one of Plusnet's older 40/20 package.

Do you know the actual phone wire distance from the FTTC or PCP to your house.

This can be significantly longer than both the "crow flies" (point-to-point) distance and the "obvious" road/footpath distance.

In my case, the FTTC is literally 10 Metres from my front door, 40 M to the PCP and another 50 M from the PCP to my front door.

So one would expect the wire length to be around 100 M

But the actual phone wire length is about 300 M, although this was a green-field site when built in 1967.

Thus on an EE 40/10 contract, I get about 37/9.

Between 6 and 700m

I suggest that your length is the likely cause - but ensure your phone line is clean by doing the Quiet Line Tests.

Also, is that distance, clearly an estimate, likely to be accurate, on the basis, say, that your line is all overhead so you can be sure of it; or is it underground etc?

You may find the Google Earth Measuring facilities helpful.

In reply to a post by mikejp:

This speedtest is via a Homeplug but is pretty similar to the results of a direct wiring to the router.

Homeplugs will affect your speed much more than Wifi or VOIP would.

A few replies:

www - My apologies, I should have made it clear at post #1 that I was NOT looking for more than 40 which is my 'contract'. Plusnet did a lot of work resulting in a move 'at the exchange' due to 'a hot line' but I was expecting much closer to 40. What EXACTLY are the meanings of 'sync speed' and 'max attainable' when it comes to what one gets?

eckiedoo - cannot see what line length has to do given the router stats?

Batboy - Homeplugs are disconnected for the test - see
"This speedtest is via a Homeplug but is pretty similar to the results of a direct wiring to the router."

My Downstream attenuation on a 300 M line is 13.6 db, compared to your 20.4 db, so indicating that your phone line distance is almost certainly greater than mine; and generally in line with your estimate.

---------

My Downstream "NOISE MARGIN" is 12.8 dbm.

As apparently there are two different ways of measuring Noise generally, I am not sure how this compares with your "20.4".

But I very rarely encounter problems of slowness etc, so my line is clearly working well.

Edited by deleted (Mon 04-Jul-16 09:56:12)

The longer the line, the greater the losses generally; and also the greater possibilities of noise pick-up, requiring message packets having to be repeated, so extending the time needed to build up a complete accurate message.

The line losses are effectively "uncontrollable", as they are conforming to the fundamental laws of physics.

However, the better the quality of the line, those losses can be reduced, such as ensuring the line is "quiet".

Some of the router stats are not directly "actual performance" stats; but are directly related to the contract.

This is also the source of the "up to" phrase.

----------

If a truck does 80 MPH on a motorway, there is a greater chance of the goods being damaged on arrival, so a request has to be sent to the supplier, to send replacements, thus taking a longer time for the recipient to get an unbroken item.

Hitting a pot-hole in the road could be compared with noise on the line; or a bad joint.

Heavy traffic on the "70 MPH" motorway, reducing the effective speed and causes congestion, as does "heavy traffic" on the Web/Internet.


Thus because of the extra time, the whole transaction appears to be slower.

There is no 'up to' in my query, but you are saying that sync speed and 'max attainable' figures form the router effectively bear no relation (other than a limit) to delivered speeds?

Using what data, then, how does the BT checker establish that my line is performing below 'spec', which it is, according to BT Wholesale.

Which of my published stats "are directly related to the contract."?

Line checked as 'quiet'.

The "up to" is frequently buried in the Terms and Conditions; and I can not recollect them being mentioned when I have progressively upgraded.

There has been quite a lot of controversy about "up to" involving such bodies as OFCOM and ASA.

---------

If the figures on the router are exact as on contract, eg 40/10 or very close to that,eg 39,999 Kbps/ 9999 Kbps as appears on my router, they are most unlikely to be measured figures; but pre-sets based on the contract.

Although not included in the router, there are low level figures, below which it is accepted that the performance is below acceptable limits, which you could withdraw from the contract if you regularly get those low levels.

This appears to be the situation that BTW has identified.

-----

I don't know precisely how BTW measures those conditions - perhaps someone with that knowledge could enlighten us?

Those low-level figures are surprisingly low, from what I have read on other TBB threads.

eckiedoo - not really relevant to this query, I fear? There is no question of any 'up to' in my query. 'Stats' posted (above) were
"Sync Speed 48998
Max Attainable Speed Varies - around 54-58
Attenuations 20.4 down 0 up
SNR. 7.6 down 6.1 up "

- no reference I can see to any contract speeds?

BTW 'identified' the line as performing BELOW the 'green' band which was, I think, around the 38 mark, no mention of any 'contract' speeds in the BTW response. It was because the line 'failed' I was moved lines. .

My question is what can be deduced from the router figures other than max values and what could be causing the loss.

Back to fundamentals such as line length, which you should try to measure "accurately", such as Google Earth - the narrow rectangular upright icon, resembling a ruler or measuring stick.

Apart from the measurement units, eg yards, meters etc, you probably need to use the Path facility, which adds up consective segments.

Knowing that length with a round about 10% accuracy, will help determine the likely performance.

The longer the line, the greater the resistance, inductance and capacitance losses, leading to slower performance.

Super BRoadband, VDSL, is much more affected by those factors than ADSL.

And as I have indicated before, my own line "wanders afar" before coming to rest at my house.

My house is literally the nearest to the FTTC/VDSL source, and in the second-nearest group to the PCP, yet other groups within the estate, clearly further away by conventional geography, are listed as getting faster performance on VDSL.

Unfortunately nobody else on the estate uses the TBB Speed Test, so it is difficult to prove in practice.

Judging by the very few results in the adjacent areas, my speeds are very good; the TBB Test assuring me that is "faster than the average in Scotland"

Try this-
http://www.thinkbroadband.com/speedtest/results.html...

"Knowing that length with a round about 10% accuracy, will help determine the likely performance." - that is 6-700m as posted. Call that 650 +/- 8%?

I am puzzled by your replies. I would have thought that sync rate and max attainable would be affected by line length? If so, why is line length relevant?

In reply to a post by mikejp:

What EXACTLY are the meanings of 'sync speed' and 'max attainable' when it comes to what one gets?

As you are with Plusnet What do you get when you look here? ... Plusnet Current Line speed In mine it show 77Mb Most speedtests I have done (via WiFi) have me at around 72-74Mb/s, I sometimes see 75Mb. That current line speed is what Plusnet use and from Plusnets own........

What does "Current line speed" mean?

The speed shown above is based on your sync speed. This is always a little higher than the speed at which data will actually be downloaded over your broadband connection.

Ta, 69 - that doesn't really shine any light on the issue, I'm afraid. My 'Line Speed' is 40 (my contract).

From what I understand, that is what I should be getting and BT are close in expectation.

It is where the loss is occurring I am trying to establish. As I said, PN did their best but could not push me above current (and talking ££'engineer visit'££, when I am convinced the problem lies outside my property.)

You appear to be on the 40/20 product and not quite attaining 40Mbps throughput.

Plusnet are limiting it to 40Mbps maximum throughput because of the product you are on. Knock off a bit for packet overheads and the Plusnet disappearing 2Mbps compared to BT and 36Mbps of data on speed tests looks fine to me.

What's the problem?

Edited by RobertoS (Tue 05-Jul-16 18:37:28)

Well, BT and Plusnet thought there was! You don't. I cannot question their knowledge.

Edited by mikejp (Tue 05-Jul-16 20:00:52)

But do BT know your throughput is capped at 40Mbps. They won't know anything about that. There is no such BT or Openreach product. They will be looking for why it isn't achieving what it should on 80/20.

In other words your IP Profile is probably 47.43Mbps and they will expect much more than 36Mbps throughput. They won't find a fault because there isn't one.

It would help if you also distinguish between BT Retail the ISP and Openreach . I can't see what either has to do with it so no idea which of them is saying there is a problem.

Edit - reading back it seems you are referring to the BT Wholesale Performance Test. The same applies - it will be comparing the throughput with the much higher IP Profile. That isn't a problem, for the reasons given.

Edited by RobertoS (Tue 05-Jul-16 20:04:47)

Quite simply, the longer the copper (or aluminium) phone line is, from the new FTTC/VDSL source, via the old PCP distribution box, to your house, the slower the VDSL will be, as measured by practical Speed Testers such as TBB's.

Your "6 - 700 metres" looks as though it is a guestimate, and you have made no attempt to define how it was "measured".

You haven't said how you arrived at that figure, whether it is a straight-line measure, or actually directly measured or some other variant.

That length has an absolute effect on the working speed that you get.

http://www.increasebroadbandspeed.co.uk/2013/chart-b...

http://www.speedguide.net/dsl_speed_calc.php

http://www.ewhurst-broadband.org.uk/?p=1526

http://www.zhone.com/solutions/docs/VDSL2_Primer.pdf

All clearly state that the Line Length (or Loop Length) are critical to the performance of VDSL, hence needing to be certain of that length when assessing working speeds.

Hence asking how you have arrived at the figures of "6 - 700 Metres".

As does the general quality of the line, including noise.

-------------

As I have indicated before, my line superficially looks as though it is 100 Metres long, which should give me very close to the ("up to") 40 Mbps on the contract - but in fact it is about 300 Metres long, hence the speed dropping to around 36 to 37 Mbps.

That length was initially established when a PO lad, trying to clear noise on the line and having remade all the obvious joints and not clearing the problem, took a closer look at the records, then we both proceeded along the road away from both PCP and my house, to a very small junction box that showed up on the foundations of a near-neighbour's house, about 125 Metres away, opened it up and re-made the joints in that - clearing the fault.

I have since confirmed it by Google Earth, also separately adding the lengths of the individual houses passed including the short right-angle crank in the footpath etc.

His sync speed and attenuation tally with 6-700 metres.

We seem to be at crossed purposes here, eckiedoo,
"Quite simply, the longer the copper (or aluminium) phone line is, from the new FTTC/VDSL source, via the old PCP distribution box, to your house, the slower the VDSL will be, as measured by practical Speed Testers such as TBB's."

I thought this line length would be reflected in both the sync rate and max attainable, but you suggest it would not be and would only show in the TBB download test?

Line length paced, so within 8%, if it matters!

Agreed - but he does not appear to understand this relationship, being misled by the sync rate etc.

Take a look at the small graph, at top-left of page 2 - and then consider whether line length matters or not-

http://www.zhone.com/solutions/docs/VDSL2_Primer.pdf

Be wary, the X-axis is in "Kft", ie 1,000 foot intervals and is the length/"Distance" of the line involved.

The Y-axis is in "Mbps" and technically the description, "Data rate" is more correct than "Speed".

Note how both the VDSL1 and the VDSL2 plots tumble down fast, rather like the depreciation of car values; particularly how low they are as they intersect the "2" (2000 feet, about 606 Metres).

As Robertos has said, the "Speed"/ Data rate loss that you are encountering is generally close to what can be expected and tolerated, given your stated Line Length, and your stated Attenuation.

The two graphs at the foot of Page 2, generally confirm that loss with increasing length.

----------------

Keep in mind also that there are many other aspects that affect the arrival of the data at your location, search for-

vdsl data packets sync

http://www.kitz.co.uk/adsl/interleaving.htm

Although this is describing ADSL, VDSL is similar.

----------------

Regarding "Speed" or "Data Rate", I raised that question at my first ADSL training session, with the Instructor, at the mid-morning break.

He had been using "Speed" throughout.

Privately he agreed that it should be "Data rate"; but somehow the Development Team/s had fallen in to the habit of using "Speed" and that was what was in most of the literature of that period; and has continued to be so.

---------------

To get an impression of how confusing it is, try doing a Search for-

speed of electricity in wires

"but he does not appear to understand this relationship, being misled by the sync rate etc. " - well, I think he does, but please explain how the sync rate & max attainable detected by my router is not correct but needs to be corrected for line length?

All you keep posting is that speed drops with line length!

Roberto - I agree with the logic of what you say, but SUPPOSE I had a profile of 47'ish - what I am seeking is the reason for the loss of the 4-6Mb that I experience, and why the line is performing below par according to BTW. I cannot recall the figure BTW produced as 'target' - it was a while back and ithe results went off to PN - but I think it was up around 38. To my simple mind, with that IP profile and a '40Mb' Plusnet contract, I would expect much closer to the 40.

At what point is the '40' limit imposed by PN? As you say, I doubt BT know my 'limit', so one assumes my line carries 78/19 to be affected by line length and attentuation/noise and then somehow by PN. What is this "Plusnet disappearing 2Mbps compared to BT"? Are you saying they themselves are 'throttled' such that a '40' product will only ever max at 38??

Because as can be seen on the various sites, Speed (actually Datarate) does drop with line Length.

There is a legal maximum limit to the Voltage that can be sent down phone lines, that drops due to the Resistance etc, thus gradually that diminishes due to the combined effects of Resistance, Capacitance and Inductance, in combination known as Impedance.

Thus rapidly for VDSL as shown on the referred graphs, that (signal) Voltage reduces to below levels that can be detected by the Broadband equipment, or "lost" in any general noise on the line, hence the QLT.

Also, generally the communications involved, say a file transfer, is broken up into "Packets" of about 1500 Bits (or fewer), each with Headers and Trailers within each Packet, giving the To & From addresses, rather like an envelope, so a 1.5 Megabyte file is broken up in to about 1.1 Million Packets, each of which has to traverse the intricacies of the Internet safely, including additionally sending back messages in similar packets, to confirm Safe Arrival, or the Receiving end notes that one or more Packets are missing or don't pass checking, so requests that those be re-sent, hence extending the total time involved compared with the ideal time.

Even the smallest Packet has a full Header and Trailer, say for a 1 Byte content. The smaller the Packet size, the less efficient is the system.

And each Packet, large or small, can take a distinctly different route through the Internet/Web - that is part of the resilience of the system.

I don't claim to know "all of it", far from that, it is a highly complex subject.

-------------


If anyone is aware of a good primer on the subject, I for one, would welcome it.

I suspect people are talking about many things...

1. The difference between sync speed and TCP/IP throughput
2. Loses due to how IP Profile operates which should be same as (1) on VDSL2
3. Loses due to how PlusNet implements its mirroring of the IP Profile and traffic management

You have an Up to 38 Mb/s service and the speed test you posted was 37.24 Mb/s single-threaded. I don't see any problem there either?

vimto - I agree there, but that was one of the better test results I have had in the last month or so (and for the benefit of others was via a Homeplug...) although I still cannot see why I cannot hit 40 with those stats and was trying to see if I could make changes to my install, but have been somewhat side-tracked by line length...

.34'ish has been the norm and the result that Plusnet acted on. Incidentally, I took out a '40/20' contract. not a 38/??

Mr S -
"I suspect people are talking about many things...

1. The difference between sync speed and TCP/IP throughput
2. Loses due to how IP Profile operates which should be same as (1) on VDSL2
3. Loses due to how PlusNet implements its mirroring of the IP Profile and traffic management "

Fascinating but no help? What about them all?

Edited by mikejp (Wed 06-Jul-16 15:25:52)

OK, your problem is not line length because your actual sync is enough above the artificial 40Mb limit that line length won't make any further difference at this point.

It also is very unlikely to be a BT Openreach issue, again because the sync is above the 40Mb limit.

That leaves it either being to do with the PlusNet IP Profile which you said is set at 40Mb - can you confirm it actually states that in the "Line speed" link that several other posters provided earlier in the thread?

Other than that it is something likely within PlusNet's control. Could be you are on a "hot gateway" but often a disconnect and reconnect would jump to a different gateway. Or it could be some contention kicking in.

As far as the 38/40 argument whilst PlusNet were using the 80/20 product rate limited to 40/20 they usually (and currently) advertise it as 38 because they can only advertise figures that at least a certain percentage of customers can achieve.

EDIT : PS - the speedtest you posted here is pretty much fine. I believe BT OR are probably confusing things by suggesting there may be something wrong with your line as it appears to be performing just fine from that result.

Edited by ian72 (Wed 06-Jul-16 15:44:58)

Thanks for clearing that up, Ian.

This is from that page
Estimated line speed:
57Mb (This may vary between 42.1Mb and 57Mb) - Checked on 2016-07-06 16:16:57
Current line speed:
40 Mb

I don't thnk BT/OR are 'confusing things' since the BTW test showed my line was 'underperforming, and as I posted, I was 'moved' due to a 'hot line'. I think it best I try the BTW run again and see if I can post the 'undershoot' details here?

Yes, rerun the test now that they have "fixed" it and see what it now says. If it is in the 36+ range then I would say you don't have an issue.

Cannot seem to be able to post jpgs, so here goes
Download speed 35.62
Ping 35.75

Diagnostic result shows red bar for 35.62 test and below
"the acceptable range of speeds 36.32-45.4
IP Profile 45.4"

35.62 is one of the highest the BTW test has produced, so maybe things are 'mending'?

That is because your speed is limited by PlusNet - you can't get to 45Mb because you are limited by PlusNet because of your package. BT will not know that.

In reply to a post by mikejp:

Incidentally, I took out a '40/20' contract. not a 38/??

I would guarantee you didn't. At best it was 40/19. And most likely 38/19.

Maybe, maybe not, Roberto, but totally irrelevant in relation to this thread. I WAS under the impression that it was 40/20, but would like a reliable 38. which is more relevant.

Maybe, maybe not, Roberto, but totally irrelevant in relation to this thread. I WAS under the impression that it was 40/20, but would like a reliable 38. which is more relevant.

My line syncs at a constant 80/20, error free. Download speed tests from various sites vary between 70 to 75 meg .... that's the nature of the beast, who said you'd get 'a reliable 38' every time you test ?

er, nobody, and not me. Stay on topic? Of course, it is obviously line length causing your drop........

Edited by mikejp (Wed 06-Jul-16 20:21:39)

You just in effect contradicted yourself.

You want a reliable 38Mbps throughput but accept nobody said that was what you would get.

We would all like a reliable full speed throughput for our sync, which is in effect what you are asking for. I tried to find the legal bit where the ISP throughput speeds are given on the archived versions of PN's website but as it is a drop-down it doesn't work so far as I can see. If it was 38/19 as I surmised, then you are getting perfectly good results.

You historic problem which was solved by a line switch is historic. Like a Monthy Python parrot.

Stay on topic? Of course, it is obviously line length causing your drop........

What are you on about ?

Are you saying that line length causes me not to get max throughput on a speed test, then you are not understanding what other posters are telling you.

In reply to a post by mikejp:

Batboy - Homeplugs are disconnected for the test - see
"This speedtest is via a Homeplug

Your problem is due to you using Homeplugs as I said and you have confirmed.

I'll jump back in here... it's complicated!

You've been sold a service that runs equivalent to 40/20 sync speeds. But what does that mean for throughput speeds?

If it were an official 40/10 package from Openreach, then your modem would not sync any higher than 40/10. However, your 40/20 package from Plusnet uses an underlying 80/20 package from Openreach, so those become the maximum sync speeds. Plusnet then slow you down in their systems so you get the same throughput as though the 40/20 limit applied to the sync speed.

So ... When the sync speed is 40Mbps, what kind of throughput can we expect? Like any protocol, there is an overhead to carrying the payload, and the payload is what gets measured for throughput.

Once overhead is removed, the best throughput speed would be expected to be around 37.5Mbps. Lines running at 40Mbps sync will not get higher throughputs; that's the best result you could get if you bought a 40/10 package from another ISP.

However, the routers used by Plusnet, which they use to employ their traffic management (keeping QoS policies alone on 80/20 lines, and keeping you to 40/20 limits on your package as well as QoS), seem to take a further chunk out of the best possible speeds. If you see throughput speeds of 36Mbps+ on a real 40Mbps sync speed, then you're probably getting the best you can hope to achieve.

In your case, that top speed of 40Mbps is artificially controlled by their routers with settings for each individual subscriber - that "current line speed" value - and their underlying settings are a matter of their choice. They could set their routers to allow throughput to match lines with 40Mbps sync, or they could choose a slightly higher limit. I don't know, but I imagine it is the former.

I suggest, therefore, that speed test results of 36Mbps are the top end of what you can expect. With that set as the high water mark of expectations, you can perhaps decide how badly you are being served in the other tests.

The BTW speed tester is being fooled by Plusnet. It sees the sync speed (and the IP profile calculated from it), and sets its minimum/maximum expectations based on that. It knows nothing about the artificial limits put in place by Plusnet. Any resulting quality indications can be ignored as inappropriate.

Finally that matter of 38/19... When we talk technically about 40/20, we mean sync speeds, and speeds that aren't visible in speedtesters,. Ofcom don't like that ... and their rules mean that the services must be marketed at lower speeds. You're likely to see these as 38/9 and 76/18 or so. Ofcom rules dictate these marketing limits, and Plusnet have to comply like everyone else. However, because the "40" in your case is artificial, the exact Ofcom-compliant value depends on the exact method of limitation. I would expect 38/19 or 38/18 to have been used in marketing speak. IMO, BTs estimated speeds at time of sale are line speeds, aka sync speeds.

Of course, all this appears moot. Aren't Plusnet moving 40/20 users over to 55/10 speeds? Which will be real sync speeds again, with 52/9 throughput.

"Are you saying that line length causes me not to get max throughput on a speed test, then you are not understanding what other posters are telling you."
Zarjaz - eckiedoo will explain it to you.


WWW - thank you for bringing some long overdue sanity and knowledge into this forum. I understand what you are saying, but out of interest I am not using a PN router. The move to '55' (whatever that will be??) will be interesting to see what happens to my speed.

Batboy - you are not reading well, are you?

Edited by mikejp (Wed 06-Jul-16 22:23:42)

In reply to a post by mikejp:

Batboy - you are not reading well, are you?

Yes, I highlighted the bit in your reply where you admit to using Homeplugs which you have denied.

In reply to a post by mikejp:

35.62 is one of the highest the BTW test has produced, so maybe things are 'mending'?

Incidentally, I have never found the BTW tester to be one for recording the highest speeds, nor the most consistent.

I've always thought of it as producing figures in the right ballpark, but no more.

In reply to a post by mikejp:

I understand what you are saying, but out of interest I am not using a PN router.

You are using the one I meant - but that's the one you connect to within Plusnet's core network - the one that routes your traffic to/from the various parts of the internet. The router you use at home, whether a Plusnet-branded one or not, plays no part in this.

The move to '55' (whatever that will be??) will be interesting to see what happens to my speed.

I predict throughput speeds of about 43Mbps. The 55/10 package will allow you to keep the sync of 48Mbps, and your throughput will then be a proportion of that, sans overhead.

I picked this bit out separately...

In reply to a post by mikejp:

WWW - thank you for bringing some long overdue sanity and knowledge into this forum.

I think almost every post has given some good advice in the context of the time they were written. Some have obviously been overtaken by subsequent disclosures, but none of them were particularly wrong at the time.

In most cases, threads on here don't get started with a perfect set of data to describe the problem, and aren't diagnosed in one answer. It takes a lot of work threading through the half-answers to figure things out .. so needs a little patience.

I suggest that you use the TBB Test and/or one of the others that graphs the "speeds" achieved during those relatively brief periods, both within the individual tests and across the two.

I have just done two TBB tests in quick succession-

http://www.thinkbroadband.com/speedtest/results.html...

http://www.thinkbroadband.com/speedtest/results.html...

To put a closure on this thread?

Following a 'tortuous' and delayed move to 55/10, plus some work by OR EVENTUALLY on my line, I now have a sync of 54+ and a measured download in the 50's, so it did work.