Right update time.
Ended up deciding the best course of action was to write a letter to them as I am terrible at confrontation, the police where never going to do FA about it (and still haven't) and I'm also just a slight cubby manchild who can't handle himself in the slightest.
So the letter in short stated that we saw him damage the car and we would be taking it to the police. That we had contacted there letting agents telling them of the damage they had cause. And if he wanted to make amends please contact my local body shop where the car is booked in.
So next day rolls round and to my surprise I had a letter in return (from the chaps wife no less) saying they admit to the damage done and have contacted the body shop and paid for the work and send there deepest apologies and her husband was drunk when it all happened.
.. So I get on the blower to my buddy down at the body shop (a great friend of mine, who's done many of my cars) he tells me that they've paid up and All is good. He then adds "oh and I charged them b**tards over double so I have some cash waiting for you when you drop it off"
All in all pretty happy with the resolve .. Just wish it hadn't happened in the first place.
Tom.