Warning very soft glamper in bunting-bedecked belltent seeking guidance on how to make camping even more comfortable!!!! 
Here's my thinking...
We currently use a full-height blow up queen size which is lovely for one person, do-able for 2, but tricky when 3 DSs get in for a snuggle! Other problems are: it just looks such a mess unless I constantly re-make the bed (I like a nice tidy tent and can't stand 'droopy' duvets!); it seems very cold unless we put a duvet under us (and this makes it very slippy to sleep on!); fitted sheets 'ping' off and annoy me; being high up means we have our heads too close to the canvas and when it rains we get all damp.
So, I'm considering 2 double SIM from Lidl (no money for expensive ones!), with fitted sheets over then taped together to create a massive co-sleeping surface.
My reservations are: will it really be warm enough? Are they comfy (will I wake up with aches and pains as if I'd slept on the cold, hard ground?)? How do they self-inflate and why don't they just deflate when you lie on them?
Thanks for any advice!