As far as I can see he attempted to leave the scene of the accident, which is a serious offence. Just because you managed to catch up with him doesn't mean this isn't the case.
Also if the police told him to wait and he didn't I don't know if that's a specific offence but it doesn't look good. I suppose the problem, as you've identified, is it's your word against his if there aren't any witnesses.
As far as I can see he attempted to leave the scene of the accident, which is a serious offence. Just because you managed to catch up with him doesn't mean this isn't the case.
Also if the police told him to wait and he didn't I don't know if that's a specific offence but it doesn't look good. I suppose the problem, as you've identified, is it's your word against his if there aren't any witnesses.
Is there any CCTV round there?
But yes what James said.