Detach that T3 wire. And please confirm the wire colours as I asked. If you have a blue/white on T2 and an orange/something on T5 coming from the same extension cable you have total garbage.

It has to be the two blueish ones from one cable and the two orangeish ones from the other. You also need to find out which one supplies the third extension and check the same for that third one.

I've had a gentle root around inside the socket but can't see a way of safely removing the wire from T3, so as yet I've not done so - I hope get someone round who is a bit more confident in what they are doing... in the meantime, I've taken better photos as requested. Hope these are more useful.

Master socket:

http://imageshack.us/photo/my-images/221/socket1q.jpg/
http://imageshack.us/photo/my-images/24/socket2o.jpg/

Socket 1 (in use - and this was the original socket installed in the house):
http://imageshack.us/photo/my-images/834/socket1.jpg/

Extensions 2 & 3 both added at later dates, and both are now unused:
http://imageshack.us/photo/my-images/683/socket2v.jpg/
http://imageshack.us/photo/my-images/703/socket3.jpg/

However, I am getting more and more convinced that, as my speeds generally seem to slow down late in the evening (particularly a Sunday night), but are generally fine in the afternoons, that my main problem is contention at my BT exchange and nothing to do with my end.

I may be able to get a bit better top connection by altering the wiring slightly, but I can't see past being connected to the test socket and still seeing a drop in speed being anything other than an issue outwith my own control. Am I wrong in that assumption, because no one seems to be able to offer an educated opinion on that point?

Haven't got time for a full answer at the moment, but yes, slow-downs are probably congestion.

But those photos show your internal wiring is a complete mess and needs serious attention. Nothing that you can't handle yourself if we are gentle with you and you are gentle with one or two wires.

The fact that ext 2 and 3 are not in use doesn't stop their wiring screwing you up, which they are contributing to.

Amongst other things, both seem to be masters. So that's at least three you have. The wiring of ext 3 looks particularly suspect but that's where I need to look closer.

Cheers RobertoS, I managed to get some kind person to come and tidy things up a little for me. The wire removed from T3 of the master socket, the two unused extensions removed altogether (plus an additional one I'd forgotten all about). The router has just been connected for 30 mins or so and I'll need to wait a few days to see how the line settles down, but with everything connected as normal I *think* the stats from my router look a little better now - more similar to what they were when connected to the test socket. Am I right?

Bandwidth: 448 / 8,096
Attenuation: 16.5 / 27.0
SN Margin: 26.0 / 14.6

Much better .

As you say, see how things go now, with your existing router. In a few days your throughput should improve a bit as well.