I remember this case, although I don’t know the lady who was attacked. The sentence seems somewhat light to me - given in the original report it was clear that he’d passed waited and then pulled her off the bike as she went past, he had plenty of time to choose not to assault someone.
I think a custodial sentence of reasonable length would be sensible in all such cases. Sadly, I can’t support direct action by the gang, even though I’ve had recent attempted assault by car.