Firstly, thanks to jac_95 for the excellent post. Maybe it will encourage BT to eventually follow Plusnet's lead in having a useful technical reference section on the web site?
A few thoughts (more than happy to be corrected/ignored if I'm talking nonsense).
BT HomeHub 1 to 2:
... They don't support VDSL (FTTC) connections.
Actually there was a version of the HomeHub 2 that was sent out to those customers installing Infinity at the time. It had one of the 4 ethernet ports coloured red and assigned for the WAN connection to the OpenReach modem. I assume some Infinity customers could still be using one.
Is it worth adding that customers on VDSL2 (Infinity or Faster Broadband) should normally have the downstream IP Profile set to 96.8% of the downstream sync rate?
Is it also worth adding that the upstream IP Profile can exactly match the upstream sync rate? Not entirely sure about how this works in different situations, but for example I was led to believe that an Infinity 1 connection with an upstream sync rate of 10Mbps could also have an IP profile of exactly 10Mbps (rather than a lower percentage).
Max Achievable Rates:
The HomeHub 5 now gives customers access to the max achievable down/up rates (raw rates?) as well as the sync rates. I believe that prior to the HomeHub 5 this info was only available from an engineer's device or an unlocked or 3rd party modem?
An explanation of what these rates represent and how they differ from sync rate might be useful.