Are you prepared to risk being prosecuted?
Have they been able to identify these specific tyres as the ones that belong to him?
Ok. But is there a match?
Even if not identical.
Yes, it is never quite that simple but if an item cannot be proven to be unlawful or stolen then it should be returned to the last known possessor.
The reality is that the police do not always do that.
You can always lay a complaint at the Magistrates pursuant to the Police Property Act or sue I suppose at the County Court. The question really is whether you are willing to risk antagonising the police in this way. They can be rather childish in their responses sometimes.
In principle though you are right.
Can I clarify anything for you?
Well, as I said above really, if an item cannot be proven to be unlawful or stolen then it should be returned to the last known possessor.