Ok yesterday my attainable jumped up from 72 to 102 and then it went down again from 102 to 73. It went down at 8.40pm and I went to the cabinet immediatly when it happened as I noticed it live, and a engineer was there.
So basically people here have reported in the past having a lift and shift can fix problems with noise but that to me never made sense, unless the dslam circuit itself was faulty and leaking noise. But after speaking to this engineer I think I know whats going on.
So the normal voice cabinet has pairs fed to the FTTC cabinet adjacent to it, the FTTC cabinet cannot be accessed by normal engineers. So a lift and shift involves swapping the pair between the 2 cabinets. My new theory is these fixes from lift and shift is that pairs between the 2 cabinets have variable noise whether its external noise or crosstalk. This engineer told me he changed pairs on dozens of live cables so he could fit new customers in, and then he moved the pairs back again at the end of the day. He seemed very surprised that it had a huge impact on my attainable speed and unlike other engineers he didnt tell me to move on and go on my way he listened to me and promised to send feedback to the area manager, he even came back to my property and looked at my graphs. Sadly since he had no idea which pair is mine he couldnt move it back and he didnt have time to move all the cables back again, he said otherwise he would have done it. But his view is if there is a problem between the 2 cabinets since its such a small distance it has a moderate chance of been fixed as it should be cheap to do. I told him about hoiw I lost tons of attainable sync twice within 3 weeks of my new install and asked him if its possible I was "lifted and shifted" on those 2 occasions, he said its very possible but couldnt say for sure as was so long ago now, he took my mobile number and said would ring me back next week to let me know if BT will fix it or not.
Also forgot to mention on both changes of speed I was disconnected, even when the attainable went up.
If we assume he either doesnt call back or says they wont fix, any advice on how to deal with this?
should I try and report a fault again? best way to go about it? or continue to accept I am not getting full performance from my line?