Thanks for your response. I feel a bit depressed about the attitude of the police as well. Vandalism and setting up bank accounts at other peoples' addresses must be crimes, surely.
I guess the police are overstretched and it is hard to investigate every incident that is reported, but it would help if they could at least offer advice based on their experience of similar crimes. In my case, I would have liked to know where this incident was likely to lead and whether where is some central way of checking whether this guy was setting up other bogus accounts and credit cards at my address. They did give me some advice that would apply if he was using my name, but I don't think he is.
I'll post to the Forum again if anything else happens.
I would really like to hear from anyone else locally with a similar experience... I've just found someone in Sheffield so far.