They have done multiple pair swaps over the last month. Although the visit yesterday was the only one with any success after the initial drop in speed.
I have been told on numerous occasions I had a line with zero REIN, RFI etc. Even so it was fine until 11/04/16 when Openreach managed to drop my speed drastically, then again on 21/04/16 and finally to the lowest level ever on 28/04/16.
If it is showing I now have REIN then it is more likely to be a commercial property between my house and the cabinet, there are quite a few car showrooms with lovely fluorescent lighting on route. Having said that I hardly think they are turning the lighting on and off every hour or so
As said this only happened since yesterday.