Go with your gut.
I have often driven to clients. Once, I canceled after scoping the place beforehand, and it was similar to what you described, for all those reasons - I don't want clients linking me to my car and possibly my home.
Are you able to park some distance away?

Also, I once went to a client who "wasn't there"  -- it turns out he regularly books girls and then isn't there but perhaps watches from somewhere.... it happens. I always then felt uneasy as I wasn't sure where he was watching me from

I'm assuming you've done the relevant checks and know that the hotel booking is genuine?

If not I'd be concerned that it's a wild goose chase (like DBLM describes) and that I would be spied on or photographed when I arrived, or that there would mysteriously be some problem with the hotel reservation and you'd need to go somewhere else (or more likely, he'll try for a shag in his car).

I wouldn't be happy with a punter waiting for me outside full stop - why is he suggesting this? I rarely do outcalls if I can't get to the room unhindered, but if it's a pub why can't he meet you in the bar if that's not possible?

Leaving all that aside, if he's genuine then he can still find out your details from the DVLA if he notes down your registration number, so you're completely right to be wary. Could you get a cab or have your security buddy drive you maybe if there's nowhere else to park?

I tend to drive my own car to outcalls and have never had any problems. Yet. 

Thank you all, I've scoped it out on street view and found another business nearby where I can park my car out of sight. I'm already cautious of this booking, the client has changed his mind about length and type of booking - it started off as a social only booking but then became an intimate booking which was when he booked the hotel and had to change the time of the booking to fit in with check-in time

I drive to outcalls but always park round the corner where they can't see my car

Unfortunately this usually isn't an option for me because of the type of outcall properties I visit. Many rural and small town locations don't have an around the corner place to park.