I've hit a slight snag and I'd appreciate some advice, please!
The floor appears to be a snug fit onto the bearers all around the boat, but doesn't meet the bearers on the CB case. It's about 6mm too high in the middle, leaving the case free (it can be wiggled from side to side, despite being stuck in the boat at the bottom). This is a combination of 3 factors - the CB case may be a little low in the hull, and the floor is definitely convex when viewed from the top, and the hull is perhaps not quite all the way down to the formers.
The floor is amazingly stiff, even my 15 stone in the centre can't persuade it to get significantly nearer its centre bearers.
I've thought of 4 things to try:
1) Try lifting the centreboard case, flexing the hull up a bit, and screw through to the bearers from the top.
2) Use a LOT of epoxy. Don't like this idea since I couldn't be sure that the seal between the CB case and the ballast tank was OK.
3) Shim the bearers with 6mm ply, including making a top for the CB case.
4) Plane away the bearers (and the floor edges). Not sure this would work since the bottom of the floor may hit the hull panel.
Any more suggestions, advice and comments welcome.