From what you have typed is that he reversed out of a drive and hit you. Pretty blatant he's at fault as he was coming out onto the road. In some case's when the road is of a certain limit you have to reverse into your driveway. I'd say he was at fault. Get a claim in. Pay the money to your insurance for legal cover because if he does not claim responsibility you could be out of pocket in the long run. Visit the docs every couple of weeks so the injury specialist can see a log in the future and to help with your claim.