You can't get a better situation for an accident, the guy's admitted,
Where did anyone (who knows anything about the situation, which you clearly don't) say that the driver had admitted it was his fault - he blamed it on the vehicle...
he's insured,
He is, but we have been specifically told that his insurance company, Tesco, are not admitting liability!

the police are dealing with it,
We were also told that, since no one was injured, the police seem to be singularly uninterested in the matter and prepared to leave it entirely to the insurance companies to sort out!

you were correctly parked.
That's not much consolation if some tosspot smashes his vehicle into yours!
It's a bit inconvenient, well worth 10 pages of dross!!!
It's not "a bit inconvenient" - three sets of owners have got to get an insurance company that denies liability to cough up for the repairs to four cars, several of which are probably 'beyond economic repair'. The amount of time that takes is not a mere 'inconvenience' for something that was not your fault.
And that's not taking into account how much time and money it is going to take to get the car fixed, if it is worth buying the 'wreck' back off the insurance company in the hope of restoring it, or that fact that a car smashed that badly is unlikely to be quite the same again, especially if it has to be 'patched-up' with filler.
Besides, its not just the inconvenience. If you cherish your car, as some people do (but you obviously don't), then having it smashed up by some neanderthal 'white van man' is emotionally upsetting too (something that you probably wouldn't understand).