As per the checker:
If you are doing and address check is less accurate than the telephone number checker because the result is not based on an individual telephone line at the premises. BT's ability to provide Broadband to your address is dependent on the presence of an existing BT line and other factors, including the availability of broadband at your serving exchange, and the length of the line connecting you to the exchange.
I found that the address checker gives a higher estimate than the phone line checker.
Sorry gg but it has nothing to do with the length of the line to the exchange as you should well know when referring to FTTC services. The OP can only get an estimate from the postcode checker (or better the address checker) as he is with Vermin ATM.
You are correct regarding the length of line from exchange for FTTC . I should have changed it to read to the cabinet. To be honest I never noticed that. What I posted above was a cut and paste from the BT checker and was posted to emphasise that the check is not 100% accurate.
guys if i was too switch to bt how mmuch notice would i have to give virgin to cancle with them ??