Staffbull wrote:
I've got nearly 5lt of builders PVA (Cementone) and am wondering if it
is the same as normal PVA woodglue?

It is. Bottle it in fairy liquid containers or similar. It keeps a very
long time out of the air and frost. It might skim over in an opened
large can.

I have measured a way to have the [floor]boards short edges sitting
on a joist for the entire span, it will mean leaving a 25mm gap at the
first wall for expansion instead of the recommended 10mm, I suppose I
could just fill the gap with sommat or put a fillet in there.

IIRC the boards are 600mm wide. So cut a fillet to the second joist
leaving the 10 mm gap. Put thick rubber foam in the gap and bring it up
behind the skirting an inch or so (the plasterboard reaching down to
it.)

You might want to tack that in place, no-one ever does. But it would
make fitting the skirting a lot easier.