Sorry I personally do not believe these stats from BT/Openreach/the Government!
I work in the telecoms industry and I hear of far too many people who simply do not receive these speeds in practise. E.g. I live less than 30 miles from London (in the Home Counties) - BT have rolled out SuperFast Broadband (FTTC) in our area - but Users can only get 1Mbps download speeds! Was suppose to be 6-8Mbps according to their system pre-installation!
Quite worrying as the original Broadband Service the FTTC replaced, worked at 1.5Mbps! BT/Openreach's answer to address the problem - cancel the Service as they cannot achieve the quoted speeds - might affect their Stats! Luckily Virgin have recently rolled out fibre services in the area and the kids have recently stopped screaming at me for us to move!