Ordering anything in a new build, where the address doesn't exist in the
BTW DSL checker, needs a survey, and then needs the survey to trigger the right details to go into the line database.
My current line, in a non-new-build, needed to go through this process. Unfortunately, BT mucked up the survey, and put the wrong cabinet identity into the database ... which caused months of problems in getting the FTTC order to go through. It wasn't an obvious fault, only noticed when the engineer turned up to get the line working.
In the end, we swapped to a temporary ADSL connection, just so that we had *something*.
The moral is that you probably can order a combined phone and FTTC connection. But if anything appears to go wrong, consider getting the ISP to swap to ADSL as a temporary measure.
I used Plusnet for this. The ordering was straightforward through the phone, but getting the problems sorted out needed me to get decent one-on-one support from someone on their online team, rather than through the standard support phone line.