Well I think you did a good job in reporting the fact that you had clipped the wing mirror of a parked car.... Most drivers would not even bother to think twice - even if they had managed to write off someone else's car ! (I live in a terraced property and it has happened to me a few times - last Saturday someone collided with my lovely car whilst I was in bed, asleep, no note left, no acknowledgement of their error... grrrrr... I have to pay for repairs or have my car written off, even though I have fully comp insurance but at the inflated repair charge rates it won't be an economical repair). I doubt very much if the police would press any charges, but I am sure some the legal eagles on here will be able to advise you.