Can't see any scam in his email on the face of it but there is definitely some 'oddness' going on.

•*Thurso's not a city
•*Why would he say "In the Northern part of United Kingdom" and not say Scotland?
•*"We are a nice couple of pensioners" makes no sense, and implies it's not a UK resident typing. That's backed up by stuff like "but now we use to travel by plane, so a car is no more useful for us"...

I'd be suspicious. Maybe ask for a picture of the chassis number and see what he says.