Unless you can effectively kill everyone of the nazi prats, giving them a black eye and a bloody nose is gonna do fuck all to stop them. Probably help recruit for them if anything.
You are giving them the attention they badly crave.
Well a couple of years ago there was a demonstration outside Lunar House, me and some colleagues went past to have a nose at lunchtime. I was in a group with a black girl, muslim girl in a headscarf and an Iranian lad. First some antis with black hoods and faces covered with scarves on their faces ran to the BNP nobs and started throwing punches - they were pushed away but were pacing about like Jake le Motta despite being real weedy little tits. Arrogant arseholes who had real tickets on themselves.
Now, i have a shaved head and sleeve tattoos. One of the antis got in my face saying "who are you looking at?". I told him to fuck off and who the fuck did he think he was. I pointed out who my pals were and he skulked off head down.
My pals all agreed these men were pricks to a man, and we all ignored the BNP. Effective strategy - we ignored the BNP as a nation and they have fucked off