What are you hoping to do about this?
Who is the registered keeper?
Ok. so who is the registered keeper?
You can always sue him for the sum that the car is worth.
Or you can seek an injunction forcing him to return the vehicle but that would cost around £350 and may fail obviously.
The problem here is that there just isn't enough evidence to be sure either way.
If you are the registered keeper then he must have shown some form of evidence to the police to get them to return the car to him. Normally they would return it to the registered keeper without question.
But either way you paid something and you are entitled to resolution upon that sum.
That would be a small claims court claim though unless this is worth more than £10k.
Can I clarify anything for you?
He must have something or the police would not have taken this action.
I have never known them return vehicles to anybody other than the registered keeper.
Yes, I'm sure they did.
That would suggest they must have been shown something.
I think probably the police don't believe you when you say that he didn't make payment. If you are saying that you had made several other allegations that were also disbelieved then that might explain it.