Taking the cushions out wouldn't stop them nicking it if they just wanted it to strip for engine parts/spares ?I recently bought a newer van. WildAx. Chatting, told the dealer I was off to buy loads of kit in Halfords to help prevent theft. He said - Don't bother. Just take all the cushions out. They would not want to have to pay out on that AND cushion makers are aware and would ask difficult questions.
Interesting approach.