How long does line training go on?
I had a BT network fault which included cable replacement. Prior to the fault, my download speeds were consistent around 3 Mb/s. Post fault it was agonisingly slow around 400 kb/s but then jumped a week or so ago to 1.3 Mb/s.
The Openreach guy came round, fitted a new master socket, measured the line, scratched his head, went away down to the street cabinet, apparently swapped over lines between there and the exchange, came back and muttered 'it's a long line' and shrugged his shoulders. And that, apparently is that. Still half the speed it was.
I can only conclude that either the line loss of any new cable is appreciably higher, or, in a more Machiavellian vibe, a company is attempting to "persuade" me to go Fibre - which I intended to do anyway once the fault had been cleared. As the Openreach guy muttered on his way out: 'There have been rumours...'