from your description the incoming openreach wires are connected to terminals A&B on the backplate of the livingroom socket and the wires connected to terminals 2&5 on bottom half of livingroom socket are feeding the extension socket in the utility room that would suggest the best conenction should be the test socket in the livingroom
to get openreach engineer you need to phone customer services and make appointment - bear in mind it is likely you will be charged £129.99 for engineer visit http://bt.custhelp.com/app/answers/detail/a_id/12439/c/
you see if a local telecome engineer will help but normally any wiring prior to master socket belongs to openreach
as it seems the change to test socket in livingroom has improved conenction speed that is as suspected the actual master/test socket and utility socket is extension. try 2 filters like this and see if that helps with noise
yes double filtering the phone not the hub
if that is not helping then you need to phone customer service and get engineer visit as I don't think you can do anymore from your end
I took your advice and an Openreach engineer visited today. He ran tests and said the line was good but he heard the noise in the quiet line test. He opened the grey BT junction/connection box (feeds my house and neighbour spurred off an underground line onto premises) on the front of the house and noted some verdigris on one or two connections indicting some water ingress. He replaced these and the short run of (chewed by an animal) cable to the master socket in the living room and replaced the socket itself. He noted the wiring to the rest of the house was "back wired" so done away with that so now I just have the master socket in the living room wired.
All his tests looked good but appreciating the fault has been intermitent and sporadic he said if this doesn't fix the issue it points to an issue underground and would require a UG engineer visit. We agreed to close the job but he's left me his mobile number to call if I have further issues.
For the past few days I am seeing my download speed at about 12 Mpbs where previously I got 14 to 15+ Mbps. I notice in the Hub log that the SNR is circa 10bd where previously it was around 6db.
13:56:11, 30 Jun. ( 5754.330000) PPPoA is up - VPI: 0, VCI: 38 Down Rate=14333Kbps, Up Rate=888Kbps; SNR Margin Down=10.9dB, Up=12.3dB
13:56:04, 30 Jun. ( 5747.460000) ETHoA is up - VPI: 0, VCI: 35 Down Rate=14333Kbps, Up Rate=888Kbps; SNR Margin Down=10.9dB, Up=12.3dB
23:05:08, 25 Jun. (178322.280000) PPPoA is up - VPI: 0, VCI: 38 Down Rate=19809Kbps, Up Rate=888Kbps; SNR Margin Down=6.1dB, Up=11.6dB
23:04:57, 25 Jun. (178311.270000) ETHoA is up - VPI: 0, VCI: 35 Down Rate=19809Kbps, Up Rate=888Kbps; SNR Margin Down=6.1dB, Up=11.6dB
The engineer's own tests before and after work measured 3.1db and 3.2db.
If my Hub runs without incidents or restarts would you expect the SNR to reduce and line speed to increase automatically or is there manual intervention required to do this?
I've seen references to lines being banded but I don't know if this applies to ADSL or is that limited to fibre?
Thanks in advance for any help and asdvice given.