Biz,
As Stoney says, there's "ample free parking" to quote many an Indian retaurant!
I had my Class 1 two years ago - you don't get the certificate there and then - it arived in the post about 10 days later.
In terms of getting from gatwick, if I remember rightly, it's about 1 - 1 1/2 miles past the south terminal, so a cab would cost you about a fiver, or you could walk it in half an hour or so - just don't raise the blood pressure too much ahead of the med
Good luck with it - I beleive they've stopped doing the best bit, which tested for epilepsy, but at least it's made it cheaper!
DW