Oh Dear! That is a great shame.
Do you have a feel for whereabouts the leaks were? Forward, aft? Where they join the hull?
I would have thought it unlikely to have resulted from ‘something shifting’ – its generally pretty robust. Could it be wood drying out through years in the dry? I know that the vertical timbers between the case sides at the forward and aft ends can give trouble, but I think Dom did work on these?
I wouldn’t use a high pressure hose, they can do a lot of damage. But just low pressure played onto joints might help. Or you could try putting water inside the boat ashore to see if you can pin down the leaks? Whilst it would take a lot of water for the inside edges of the box you should be able to test the outside edges?
And I wonder if she would ‘take up’. The ‘logs’ which join the case sides to the hull are large pieces of timber and if they have dried out might have shrunk. Again, water inside the boat for a few days might help diagnose this.