We are very aware of this problem; and whenever we hear of a planning application for a new development we raise the issue of FTTC at a very early stage, and prior to the planning committee considering the planning application.
If there is uncertainty regarding SFB then we would object to the planning application, but in practice have never had to do so, as we have "educated" local councillors in this respect, and provision has been made for both cabinets & ducting prior to roads & footpaths being laid.
We reinforce to developers that SFB is a selling point usually quoting RightMove who say:-
Broadband is ranked as a more important selling point than off-street parking and access to amenities like shops. Even being near that great British love – the local boozer – is less important than the ability to get online.