Park it up in the long stay and stick a clamp on it.
http://www.argos.co.uk/static/Produc...er/7404197.htm
Alternatively, pop to Wickes and purchase 4 concrete blocks,place in boot. Pitch up at the long stay c/park, and remove the 4 concrete blocks from the boot.
Removing one wheel at a time,place one block under each disc,and put the wheels/tyres in the car (you've done this before).
The above will ensure the car stays where it's parked,and the tyres won't suffer from selective premature flat spots
I've already left........................>