Abandonment because of a coach being violent towards me

Joe your not on your own mate, It makes me sick when the R.A. shy away from this
despicable behaviour from idiots like that. No wonder the reports about new
referees are declining they need to grow a pair and stand up for you. Think next
time you get his team you won't get a beep from him.
First priority is safety. If you feel threatened, you should abandon immediately. Forget names or anything, the FA can sort that out later, your main concern should be safety.

If you don't get a name, make sure you put in a misconduct report for that too. Like I said, the FA can deal with that. The coach and player is digging his own grave at that point.

Make sure you record what minute you called the game off, why you did so and what was said or done to you.

I would say you handled this fairly well, apart from confronting the coach at the end. It's not worth the aggravation.

Was Coach B from the same team by the way? If so, he sounds like the sensible one out of the duo. Sometimes it's worth asking him for a name or approaching him if there's an issue.

Once Coach A has been dismissed from the game, I would assume that duties now fall to Coach B. He's your point of contact so don't even engage with a person as angry and violent as Coach A. Just calmly inform to Coach B that unless Coach A leaves the vinicity of the field of play, you will be forced to abandon the game.