Common sense
There is more to this issue than just line speeds. I had an issue where the cab I was connected to was 2.4km away, I could see a cabinet from my office window. There was drop wires, and all the infrastructure was there, all they needed to do was hook me up to the newer cab.
I had inconsistent speeds of 2mb! Not only that, because the line was aluminium for over 80% the quality was awful.
My complaint went up to director level and yet still, because my PSTN service was working with no problem, they wouldn't do anything.
If Openreach/BT use common sense and put more capacity in local cabs so they are taking the distance down to sub 500m, a lot of these problems would be sorted.
I almost ended up paying £6000 to get fibre to the prem installed, instead, I realised it was cheaper to just move house!