I broke up a fight between a young scrawny bloke, who I was friends with, and an older big guy. Got me a good insight into the justice system and a holiday. So no I would not break up another fight.
The law is not really on your side with interventions
its a long story, that came about when I had responsibility for a workplace where threats of violence, and even assaults had taken place.
There was 70% female employees, and the problem comes about about if anyone gets injured during your intervention, even the attacker.
There are several issues, but "reasonable force" is the crux.
My interpretation of reasonable force, when a nutter is attacking a woman, is a strike to a nerve point, grappling is foolish.
I was told absolutely, that my employer would give me no legal support, if this was my technique.
I was threatened with violence on occasions, but every time they backed off, when I made it it became perfectly clear I would fight like an animal if attacked
( except once when a scrawny little mad guy smashed a glass, and I decided to run)