Your county council should be the Highway Authority, and most of those have maps of the highway boundaries somewhere on their website, so you should be able to see if it was within that boundary and therefore their responsibility.
If it's outside the Highway Boundary, I'm not sure if it would be the District Council or not.
I hope it's a just a couple of doors needed but the dent in the roof is not promising...
If it's a write off, buy it back and stick a cage in it? Should mean it removes any issues with shell strength, plus 'race car'