I was probably the first person on our cabinet to get FTTC and I used to get about 27.6 Mb/s download but after a year this dropped to around 25 and the crashed down below 20 managed to get a line fault fixed which got me back to 23, but after several nightly 'resets' recently I assume by the DLM, it is struggling at most at 21.
Cabinet 41 on Wakefield exchange.
Some stats from Router:
Data rate: 4171 / 22400
Max data Rate 4068 / 29642
Noise margin 6.0 / 8.1
Line Attenuation 44.6 /25.7
Signal Attenuation 32.9 / 22.3
The BT Wholesale speed test says my profile 21.68