Since posting we have both done a cursory examination of the substructure using a fiber optic scope. Looks like the area between the cabin sole pan and the hull is reinforced with a combination of chopped and woven 'glass although it is certainly not overbuilt. The compression post on this particular boat has rotated out of position about 3/4 of an inch and about 30 degrees axially.
Seems like the thing to do is to add some more reinforcement paying particular attention to any gaps between structural elements and resetting the compression post and reattaching maybe with 5200 or some other strong but relatively low modulus method.
Care should be taken to taper and reinforcement to avoid creating any stress risers.
Good luck and let me know how it turns out.