The question was whether I need to inform my insurance even though they will have no involvement.
In that case the small print in your policy will more than likely say that you do have to tell your insurer. They will want to know because statistics says that your car is more likely to be involved in further accidents now so they or whoever you switch to need to charge you more for it next year (when i did it online about a year ago, every quote i had went up about fifty quid as soon as i mentioned a very similar car park scrape paid for by other driver’s insurer) . And at renewal time they will find out anyway through the database thingy, as the other bloke will have to tell his insurer who he bumped into.
[edit] The drink/speeding comment above is ref: the other thread with loddrik argiung how much he was speeding by, and the arising troll thread about how drunk is drunk. But rest assured that if your whole family was squashed flat in your parked car by a speeding drunk truck driver, assuming you weren’t in the car and so seeking car insurance the next year, as a consolation and to assist with the grieving process your premium would still go up fifty quid as that accident makes your next car more likely to get squashed flat by another drunk truck driver a second time. Aren’t statistic great?