Well, there should be someone coming along this afternoon to install FTTC service at a good friend's house. The DSL there has been very intermittent for years with numerous disconnections daily.
The FTTC service will be installed on a different telephone line and the ADSL will only be ceased when the FTTC has had all the faults ironed out. At the moment ADSL is limited to about 8Mbps to help with stability.
The cabinet is probably 600-700 metres away so FTTC won't achieve great speeds. The estimate is 30.9Mbps down and 5.8Mbps up.
My suspicion is that there will be similar problems on the VDSL as the two phone lines come into the house in the same cable which was severed a number of years ago some distance from the house during a burglary attempt.
I'm quite looking forward to this as it's my first experience of a fibre install even though I'm not expecting things to go smoothly!
I'll post an update and some stats later.