My install SHOULD have been done before I moved in, but in the end was actually done about 3 weeks afterwards, over about 3 days, and then a week later the work in the street was finished (Openreach said Barratt hadn't done something, Barratt said it was all Openreach).
I managed to get someone out yesterday so I now have a nice new end on the cable (and an additional box on the wall that wasn't there before?!) with a green light on the ONT, and as my Plusnet order activated over night I had a connection this morning!
So far there's been no mention of charging me, and I'm not sure how they would as I arranged it with Openreach and not via my ISP... Fingers crossed it's all covered by the developer.