Hi there - we are going to Tuscany in summer, flying to Pisa then hiring a car. The car hire company has quoted 80 Euros to hire two car seats - two boosters actually, as mine are 7 and a very large 5. That seems extortionate, but obviously I don't want to pack car seats! A friend had heard of some different options - one that comes like a back pack, and inflatable ones. Has anyone used them at all?