I managed to get the TARDIS walls up today and I got a first coat of paint on.
The walls are an inner layer of 9mm plywood with an outer layer of 7mm. I’d use the word laminate, but that would infer the use of lots of glue and clamps. There was some glue between the two layers, but only around the holes.
This two layer construction method meant I didn’t need to do any complicated joinery. The whole lot was routed out with a plunge router.
One other part of the illusion is that the side of the TARDIS facing the road will be decorated like a door, but won’t actually open. The access door will be at the back.