Sorry to hear of your vehicle being stolen by some nicely spoken low life thief
Guess the moral of your story should be don’t trust anyone
On that front, if I was selling, I‘d be reluctant to even take the guy out for a drive (with him being just a passenger) as you hear stories of armed robbery during test drives. But if I ever did take someone for a drive, it would be in an insured and registered vehicle. That way I’d still be covered even if the passenger pulled a knife and stole the vehicle through threats of violence (and he can happily have it as the insurance will pay me)…
I wouldn’t ever let anyone drive off on their own in my registered and insured car unless they provided a 100% of the sale price as a fully refundable deposit so they could get their money back should they not like the way it drove. Why, because you hear of drive-offs or even of people making 1/2 payment with promises to pay the rest but they never do….
And if some buyer doesn’t want to abide by my conditions around my car sale, then they can go elsewhere and buy/steal from someone else.
And because the car would,be registered, I‘d want correct details so I can fill in the transfer forms so as not to be getting tickets as the last known registered owner… As for proof of who they, I’d want 100 points of ID just like banks do…
Sadly it’s too late for you right now but chalk it up to a learning experience and hopefully you’ll be lucky enough to get your car back in the same condition it was the day it was stolen.
PS: if the car is unregistered, you can get a one day unregistered vehicle permit and insurance cover note which the potential buyer would pay for (on top of the 100% deposit)… If they are serious buyers, they’ll accomodate the sellers reasonable requests.