Unadopted roads and unmarked roads are very awkward to advise on liability. It is your duty to ensure your path is clear before proceeding and the other party's duty to ensure that they can stop in the distance they can see. He clearly could not if he hit you and ran over your bike. If they were on an identified road, i.e. named, then you MUST give way to traffic coming from the main road and not impede their path. You would need to refer to an accident investigator to give an opinion on whose fault it was. I would leave it in the hands of your insurer, I would guess that they will say it is either your fault or a 50/50 situation.