Lots of things, I think. But if your expectation is for the police to attend and investigate every minor crash that happens every single day on the roads around Britain, then I hope you're not also expecting them to go to other things too, like crimes & stuff.
I think perhaps you underestimate...
Assuming he stopped at the scene, no other property apart from your van was damaged, and nobody was hurt, there's no reason why he'd have to make a statement. All he's legally obliged to do is give his name, address and registration number. Unless something else was amiss, the police won't even...