I certainly remember this being possible, I remember a Corrado G60 owner being particularly keen on having G60 and then his initals. It was blind luck that he saw a car with the right plate parked up. He hung around and waited for the owner, a sum of money changed hands and he got the plate. However unless you've already seen a car with the plate you want it would be pretty difficult to track down an address from a number plate. Unless you have a friend that goes to work wearing a tit on his head.