Write down as much as you can remember: date, time, road name and where, colour and make/model of car, driver approx age and appearance if you can remember any of this. So that you can back up that it's the same person if you see them again. If you see them again I would note the reg and report to police without interacting with them.
Roadsafe will have better advice. I don't know if it's helpful to report now in case you see them again but not for a long time.
If you are worried about being attacked next time he sees you, consider a helmet cam but i'm conflicted in saying that, because it really seems sad if you have to do that to feel safe :(
Write down as much as you can remember: date, time, road name and where, colour and make/model of car, driver approx age and appearance if you can remember any of this. So that you can back up that it's the same person if you see them again. If you see them again I would note the reg and report to police without interacting with them.
Roadsafe will have better advice. I don't know if it's helpful to report now in case you see them again but not for a long time.
If you are worried about being attacked next time he sees you, consider a helmet cam but i'm conflicted in saying that, because it really seems sad if you have to do that to feel safe :(