Best helmet camera?

It was only a week or so ago that I thought it would be good to ask if there were any recommendations around a helmet cam for recording other road users. Having been knocked off on Saturday when the driver didn’t stop, having the situation recorded would have assisted the Police in tracking down the driver concerned. What I think I should be looking for is something that isn’t as big as a GoPro [I have one of the first ones] and has the ability to store many hours of footage. I’ve seen some for a car, that re-write over the same memory unless you stop it and tell it to record permenantly… any advice would be gratefully recieved.