If so it is something of a landmark if the Police use this to identify and prosecute.
In what sense? In the bb gun case, yes it appears so. Identify, well plenty of cars have been identified through footage. Person, yes, it's done very well here. It seems very likely by the angle that it is helmet camera footage. If it was CCTV footage then I compliment the police's investigative skills as that would be harder to locate.
If you mean more generally someone who attacked a cyclist, we had benborp of this forum who was assaulted by someone and the overall incident was captured on film. Unfortunately there wasn't a conviction for assault as they weazled out of it saying it could have been some elaborate whirling around on ben's part. The driver was convicted of a much lesser charge.
This case immediately made me think of this where the helmet camera probably hasn't captured the pellet flying, so in court or the CPS may benborp style argue that the driver was merely threatening the cyclist and that any injuries could have been caused by some other unknown person in the area with a BB gun. I just hope it doesn't go that way, but after the case on this forum I do wonder. In the end I hope it goes to court, we've heard of plenty of cases of bbs at cyclists over the years and you can't really let these people go when rumbled on film.