Repair water damaged door card?

[lufbramatt]

Door membrane has come away in one of the rear doors on my E39, resulting in the bottom inch of the door card becoming waterlogged. It looks perfect from the "seen" side, but the board has started to delaminate on the inside. There's enough board left for it to hold it's shape but it's gone a bit bendy+weak. Think I caught it just in time.

Replacement not really an option due to a unusual trim colour= £££.

I'm thinking carefully peel away the leather at the edge where it's folded over, mask off the front to prevent any accidents, then lay up some GRP over the board to give it back some structural rigidity. Sound sensible? One of the plastic brackets has also come away due to the bit of board it was glued to coming off, what's the best thing to glue it back with? I was thinking some tigerseal/ PU adhesive.