Congratulations, Si, and welcome aboard!
I'm also UK based (Croydon, south London) and bought my first Boxster (a 2002 2.7 tiptronic with full leather and pcm1) on Tuesday last week after three days and nine hundred miles of travelling across the UK to look at two other examples. Unfortunately some twat ran into the back of it last Sunday, but only the bumper has been damaged and I've already got another in the right colour which I'll be swapping this weekend. Hope you have more luck with yours.
Other than that, the car is superb. A bit of a contrast to my previous car, an '88 Citroen 2cv6...
Enjoy the ride home. Mine should have been a 100 mile journey home from Milton Keynes, but as I was enjoying it so much I deliberately took the longer way around the western half of the M25
Rob