Have to say though that R124's plate was a good example of how not to do it. It's a prefacelift E38 so it could be anything up to an L plate anyway - so sticking a K plate on it with 2 digits (There are numerous of normally issued non personalised plates out there with two numbers) means it looks like.. a K reg E38. People often get confused with this - there is a guy in the office at work who has a regular car with its original plate and gets asked if its 'private' because people get confused.
If he had K4 PDC instead, this wouldnt be the case, as there are no normally issued single digit plates.