I extracted the cooker/sink unit and the fridge from the caravan and set them in their planned positions, along the side behind the driver seat, and mocked up the bed. Back to the drawing board - the folding principle worked but we had not anticipated just how much the back of the van curved in - some 6" of mattress overlapped the curve of the van at the top.
Then on the other side, we wanted to determine the space for the toilet cabinet, so we used a cardboard mockup and made a wooden loo sized box - clearly going to be tricky to overcome the intrusion of half the wheel arch - the loo will need to be higher to get over it, making it too high to sit on, so we'll probably need to build in a partly raised floor within the loo compartment, but will first try mocking up a smaller loo (resisted so far for its smaller capacity) to see if that works any better.
We made the second attempt on 4th November and could see better that we needed to cut down the sink/cooker to the minimum (to maximise 'corridor' width) and how the bed could work - build storage boxes either end so reducing the amount of bed board to fold up, though this has the disdvantage of involving smaller, non standard mattresses. Also we managed to decide on the loo to buy and we need this to really sort out the layout. Our wooden cube mockups only go so far. But the important thing is that we have done enough to be able to take out the old floor and lay the new one - see here
