I understand why so much of your post concentrated on the negative advice...
However, I'd have preferred that after you told us that BT did something physical, you told us what they did, and what the impact on your service and statistics was. Same routing of cable, just with twisted pair now? Or new routing to avoid power entirely (like your unofficial fix)? SNR doesn't drop? SNR drops by just 1dB instead? Change in what can be heard on the QLT? Changes to the radio hum? Reduced error rates? Has the problem disappeared, or just "reduced to insignificance?"
Yes I am sorry maybe I didn't say as much as I should have.
Firstly the QLT that was the subject of the first BT visit didn't resolve anything as far as the BB was concerned and in fact I learnt that what I was hearing was normal (background hiss and a little hum) but the guy replaced the old master socket and re-crimped the gable joint in jellies as insurance.
After that visit the REIN was as bad as ever with 6db+ snr hits causing re-syncs. In desperation I tore out the remaining length of figure 8 ty-wrapped to the big incoming power conductors to the house along the barge boards, bear in mind the REIN events/re-syncs only occur on 3-5 days a week so patience is required at each step however I was able to establish the hits had dropped in magnitude to ~3db and that was no longer sufficient to knock out the BB (as it runs a tsnr of 6db). At this stage I was left with a phone wire waving in the wind.
After collecting more evidence Pnet/BT agreed to another visit. The engineer did a very thorough job with his tester, looked at the plots I had printed for him before/after the drop cable move and said yup it's REIN by induction from the power cables and that drop cable needs replacing, initially from the house to the flying part but then said well the whole lot's a bit old I will just do it all.
Given the problems already experienced he decided to clip it to the brickwork rather than the barge board that has the effect of a ~200mm separation along the length concerned (~5Mtrs).
Needless to say whilst BT were here there were no REIN events however today there have been three so far, each one has been limited to no more than 3db. This indicates it is the re-routing of the cable that has done the job and the actual change in wire type is acting as insurance but may solve the wet problem I also had (snr droops in rain).
ATM I am watching and waiting before changing anything else though next up is the RJ11 connection to the router that will go twisted to further reduce susceptibility.
If all goes to plan and the droops remain just 3db I will be able to reduce the tsnr and increase the speed a little. Ohh I almost forgot radio5 live, it still gets blotted out but I did receive a nice letter from the BBC basically saying they have no resources for investigation, it's up to householders to self diagnose, trace the offender and ask them nicely not to do it, or alternatively had I thought of buying a DAB set!!
Once again thank you to the nice people here

Sometimes it's just moral support to continue the struggle to achieve how it should be in the first place
W8960n on Lonnggggg line
Edited by fourtytwo (Wed 07-Sep-16 17:35:05)