The Plans

Above are the original plan for the bed to go in the van, and a rough copy of the dimensions of the van (to see whether I had enough carpet/insulation) (not greatly accurate diagram, but gets the principle across).

The original idea for the bed was to be two rectangular boxes that would stack ontop of each other during transit, then to make the bed, stack them next to each other, clip them together and tighten around the wheelarch, and then fold out a flap at the front to make a single bed with the front seat rolled forward, and also that would then fold out again to make a double bed.

However, once the van was bought, this plan was not viable due to there not being enough room between the wheelarch and van door for a supporting leg to fit. Therefore, a fold up bed like a friends van was thought up.
However, this, too, became problematic as due to the shape of the rear of the van, a flat surface in the cargo area of the van would not fold up against the side of the van. See a future post for how I managed to work around this.

Also on the plans were more questions than answers, regarding whether a double airbed would fit (the one I had would not) and other bits and bobs that I'd picked up from reading forums etc.