Hmm i reckon technically it's your fault as you were over the white lines, but i don't think it really was. I had an accident pulling out so I could see as there were parked cars in the way - it's very frustrating - in my case the cars were parked illegally close to the junction, I accepted the accident was my fault but told the police to get these cars moved/ticketed, surprise surprise nothing was done. In your case - if he scraped the side of his car (not the front), that makes it sound like he did get past but then moved so as to hit your car with the side of his, so he could have prevented it. Don't know if you'll have any luck fighting this but I would definitely give it a go, your insurance company may waive your excess or something as a good will gesture.... Good luck anyway :-)