Cheers folks!
Unfortunately, paint goes from bad to worse. I painted the floor and lower interior with MATT pale stone, which has managed to come out in a horrid, ripply semi-gloss finish. I thought that it might look better if sanded down, but it then became apparent that it was only surface dry, and as soon as I started sanding it turned tacky again and I now have a zillion bits of 1500-grade sandpaper embedded in a floor that looks more like carpet now.....

It's currently on a radiator (not directly) to see if that dries it out properly....
The shell is painted, but needs lots of touch-up and tidying, and when I pulled the doors off, it became apparent that the paint in the cracks, in contact with blu-tack, hadn't dried either, so I now have to wait for that to dry or else I'll risk putting blue fingerprints on everything.