Anything can be fixed, the surreal could involve moving the house a mile down the road.

Seriously you need to get the actual stats from these other properties and confirm they are on the same exchange as you.

The estimate was wrong for your property - which may mean people are under the illusion they have better speeds than they really do, i.e. have never investigated further, or there is something unique about your line. It is correct to say that a telephone DOES work when plugged into the test socket?

If the 70dB attenuation is correct for your line then nothing more to be done really.

If the 70dB is down to a fault/odd wiring situation then something might be possible, but since broadband is a best efforts service, Sky and Openreach can offer you, take this speed or let you exit contract with no penalty.

In reply to a post by Anonymous:

I can see that improving the house cabling would reduce the amount of downstream connection speed loss compared with when plugged into the test socket but is there anything I can do about the 1.1Mb speed compared to the 3-5Mb I was predicted when the house wiring is bypassed please? Should I call sky and ask them to get an engineer to check?

When you use the test socket, are you plugging the router into the filter using just the short ADSL cable, and the filter straight into the socket, or are you using a plug-in extension lead as well to reach the socket?

In reply to a post by RobertoS:

In reply to a post by Anonymous:

I can see that improving the house cabling would reduce the amount of downstream connection speed loss compared with when plugged into the test socket but is there anything I can do about the 1.1Mb speed compared to the 3-5Mb I was predicted when the house wiring is bypassed please? Should I call sky and ask them to get an engineer to check?

When you use the test socket, are you plugging the router into the filter using just the short ADSL cable, and the filter straight into the socket, or are you using a plug-in extension lead as well to reach the socket?

No extensions!
I shall knock some doors and try to get some of my neighbours actual stats.
Will report back! Thanks for all the help so far!

If you don't know their phone numbers, get those as well. We need all the straws in case they need clutching at.

A question for the original poster...

What speed did an old dialup PSTN modem connect at? Or put another way, was there ever a DACs on the line?

If the other properties are in the 20dB attenuation region, then your performance may because of the presence of a DACs or partial presence. While a DAC's should totally break xDSL, if I recall we have seen a few get some signal just about.

Another option is that if your line had intermittent audible noise on it with regards to voice telephone calls, then an RF2 filter may have been fitted by BT. For compatability with ADSL this needs to be changed to an RF3 model.

Did the OP ever say he had a dialup PSTN modem?

It's a new build. Is it likely to have a DAC?

Probably not, but am wondering whether half a DAC was left in the network somewhere, new build usually only means new cable for the last few metres.

Not spoken to neighbours yet but moved the router to another socket to see how disconnecting the bellwire helped back where the router started:

1.0Mb from front socket
1.1Mb from test socket
0.39Mb from original socket

Not terribly impressed with house wiring or street wiring!

Original socket shows it's the house wiring. No evidence on the street wiring!