"Openreach Twitter feed that all FTTP expansion was on hold and had been for a while"

All is the incorrect word, in Wales as the SuperfastCymru contract has ended there is a hold on work via that, though some limited areas and cabinets are still popping up, presume ones with very very simple issues that delayed go live earlier e.g. line card failed so an easy swap, on FTTP things like one splice needing to be redone.

It could have been that the person was replying to someone in Wales then.

It was, but given ability for people to find things and not read the context including the 'in Wales' avoids future confusion e.g. quoting your post elsewhere without access to the surrounding context