Personally, this screams as a private sale end of story but......
Just to play Devil's Advocate (again); Could you been seen in court as a motor trader?
What do I mean?
You took that car as payment for a building job, or in lieu of cash payment and had no intention of keeping the car and therefore (in a round about way, like us taking a PX) were looking to profit from the proceeds of the sale, maybe (arguably) make more than the building work was worth? You could be seen to be trading a car.... Same as if I took a piece of land in PX against a car I suppose (I have taken some strange things in chop before).
Anyway, you have had a taste of what us Dealers go through on a daily/weekly/monthly basis and I would appreciate you telling all your friends in the pub who say dealers make a fortune and are all dodgy some home truths and that we work bloody hard to do the right thing by people whilst keeping a roof over our heads (that we will pay a builder to repair )
Good luck.