I took the photo of the M3 that I posted from the sliding doors at the entrance, just to give you some idea of bearings. There is a desk right there and everything else is cordoned off. You ring the bell for attention and someone will come out. Leave your driving licence on the desk and they will take it away and come back with the keycards and a delivery note to sign. Go and have a look around the car for half an hour or so (you do this on your own). I suspect you've watched about 3 million youtube videos about the M3 so you'll know all the screen options already
If you're happy just go in and sign the piece of paper and drive away. Presumably by then your son will have sussed the music and it will be blaring away with the volume up to 11...
It's quite a labyrinth of industrial estate streets around there but the navigation gets you out just fine. It's not far to the dual carriageway but it still took me a little while to pluck up the courage to put my foot down. It's all 40 / 50mph dual carriageway around there (don't know if you know Leeds roads at all, I didn't) so best not to floor it until you get to a motorway. You get to the legal speed limit extremely quickly. Make sure your head is well planted against the seat back BEFORE you do it!!!!
I had to drive for about 20 miles before the autopilot cameras calibrated. It won't switch on before then. There is a blue circular progress wheel around the steering wheel icon that tells you how it's doing.
I am currently thinking of excuses to go out for a drive.
Enjoy! I expect you might wake up early tomorrow...