We have now received the estimate of the charges from BT. These are detailed below.
Estimated Build Cost: Onsite survey required to confirm charges
The build charge includes the estimate for the work and materials required to deliver the service. It also includes the connection charge.
Well that's helpful.
Given that others have now had post survey quotes coming up much lower than desktop quotes I was tempted. If they had said say, £5k on the initial quote I might have gone through for a full survey in the hopes of getting £3k or so, which I would be willing to spend.
Obviously this gives me absolutely no clue!!