I don't think I'm going to @
Moda - the police are already involved, I called the department (Road Criminal Justice Team or something along those lines, sounds like a really bad superhero outfit to me) yesterday to establish what's happening. I have been assigned a case officer and she told me that they had only received my form on Tuesday (a week after I handed it over to the police station!) but that they would be writing out to me yesterday evening (2nd class, so letter could arrive beginning of next week) and sending out a questionnaire to the witness (meaning they must have been in touch with him already, as he only left his name and phone number) and informing the registered keeper of the car that they were investigating a case against them.
The thing for me is I'm not all that greedy. If the person responsible pays the cost of having my wheel built (£35) and gets a driving ban for driving off, I'll actually be satisfied with that - so long as this is the first time they've been involved in an incident of this nature, of course.