I wanted to fill the gap between the sideways seat and the sliding door. It is a wasted space and I need to cover the speaker box from the bulkhead. A hinged frame box would make an ideal book cupboard. I decided to use sturdy timber for the frame, and 9mm ply for the top, and 6mm for the sides. This should make it strong enough to be an extra seat.
I made a frame that could be screwed to the seat, bulkhead and floor. The cupboard would also take up some of the step well. This made making the box more difficult but added an extra handy storage pocket to the cupboard.
This cupboard would make a great place to add one of the rear speakers. The sound would reflect around the kitchen and door area giving it a wider sound. I cut the cupboard sides and fitted a speaker to the front panel. I cut and fitted the side panel and the hinged 9mm top.
I later added the electrics panel inside this box, with a battery meter level indicator, a 3 way 12v socket unit and switches for the fridge and sockets.