I would look at the possible leaking points on the deck outside. I own a H38 so not to different. I only see the port winch and the line blocker installed above that hard plastic headliner in the vanity area. Start by the these as this will be easier. Taking out the hard plastic headliner is a major job. You will have to remove the medecin cabinet I think, remove a couple of screws, cut the sealant left and right of the plastic headliner and start pulling. It is usefull to imaging the building sequence at Hunter when they build the boat. As far as I know this headliner was attached to the deck element and the deck was then lowered onto the hull where the interior elements were already installed. Search for the words “Hunter factory build” on you tube and you will see what I mean. Good luck!
