In reply to Chloe:
We have a Vango comfort 5 double, which is very warm and comfortable, but a bugger to pack down and quite big when packed (as will the Shangri La 10 be), so we mainly use an Outwell reel one which is twice the thickness and packs to 1/3 the size and take a battery pump.
No issues with either on getting bumped around.
From experience with 2 singles, someone ends up down the gap, even with the Thermarest couple kit.