We're keen campers - one reason for buying Jazz was for wonderful magic seats as space efficient alternative to buying another estate car - and were interested in trying out using Crosstar overnight as people do in Berlingo et al. In years gone by we'd done the occasional stopover down to Alps in French motorway 'aires' in Peugeot front reclining seats (survivable if not very pleasant).
With the Crosstar, from a little experimentation, it looks like you have two alternatives: a) reclining front seats put to maximum backward slope or b) lying on our (thermarest) camping mats in back with seats down (and some soft luggage in wells behind front seats to give a bit of extra length).
Has anyway given it a go? I could imagine the car, being so bossy, might want to alert you all night that you are still in the car with your keys and have the windows a little open for air?
Any other camping Crosstar owners?
PS: we camped in very minimal Suffolk campsite this last weekend: two people, big tent, two paddle boards, table and chairs, Kelly kettle and firewood, Trangia and food, bedding, books, clothes for all weather conditions et al. AND it ALL fitted in. So we're very pleased!