Laser woes.

Laser hulls aren't hard to get hold of,. maybe you should consider that rather than a PITA repair.

Yes Davidyacht.   Would you think it worth cutting a 150mm hatch into the deck beside the mast pot to check bottom block is still intact. If deck and hull separating likely of an age that other areas are failing.

There is some water in the hull but not a massive amount, probably a pint.
Should be a easy fix, force a gap then sikaflex, remove blocks and clamp back together.

Had another look, it appears the deck is detached from the hull on port side, I think the boat is actually distorting, you can easily push the hull inwards.

There are certainly steel reinforcing rods in the board. The matrix is pretty brittle though, I'd be surprised if it could bend much, but warped daggerboard is the first thing that occurred to me with the symptoms. As well as trying someone else's foils in that boat try those foils in another boat.