I may be wrong but have you not stated the same thing on each line?
Nope, first line was a statement, second line was a question. First line was about ADSL, second line was about VDSL.
that said. On a non LLU exchange, SHY have to buy the service from someone else (BT wholesale) and may run that to a limit that uses all of the service up!! (this may be a good service nor not so good depending on the number of users on that exchange). On an exchange that they have a direct LLU service themselves, then they may run that at a level that is zippy and fast!!!. For me on ADSL LLU and now SKY FTTC I did not have any performance problems
Your post suggests that Sky fibre on exchanges that Sky have LLU'ed is faster that Sky fibre on exchanges that is not. That's what I suspect too.
Perhaps what I'm wondering is whether Sky can install their own backhaul from an exchange which they haven't LLU'ed for the purposes of providing faster speeds on Sky fibre, or whether they can only install backhaul on an exchange which has a Sky LLU presence on ADSL.