Here we go. I used my foam template to get a pieces of foam oversized and glassed. Of course it was a bit of a job thinning out the piece first as all my remaining foam is thicker now. No pics needed of all that fun.

Pic 2 is more fitting and working out what to do around the trap door in the corner.

Pic 3 shows that I have just one side glassed so I can play with positioning internally. The idea is to get the side wall cavity as wide as it must be and not a millimeter more.

First foam piece glassed

A trial fit

Making a minimum gap