I'd have thought around 1k would fix it at an independent body shop. Obviously dealers will charge a lot more, and probably sub it out to an inde anyway!
I had a similar issue years ago, but the guy in the outer lane swung round in front of me and I went into his drivers door. Since he was trying to turn right from the left lane, of a dual carriageway, he was clearly in the wrong. I went back a few days later and took a load of photos of the approach to the roundabout and all the signs. I put them together into a letter and sent it to the insurance, who agreed he had no chance of a claim (did I mention my car was undamaged, his 205 was seriously stoved in! And he was claiming against me of course...)
It took 6 months to get my excess back, which the insurance helped themselves to from my credit card!