Yeah, just don't forget that in the UK if the car park is open to the public exactly the same laws apply as they do on the public road. You can (and people regularly are) be nicked for driving dangerously/driving unisured/etc on a deserted car park.

One poor guy was done for drink driving, after driving a couple of hundred yards across his own field. He was hosting a village fete in the field and while the fete had ended the gate to the field was still open and a few people hadn't yet left.

The law really can be silly sometimes...