He's being a Gorilla

If you missed the opportunity to escape and avoid and the guy is now fronting up and posturing

the chest out, i-am-big man, what to have a go type poke you and tell you to f$%#@#@f sort of gorilla posture

Start talking, rise hands and start leaving
this is not ufc you dont have to fight
go home

Sorry mate i apologize and leave

I have 4 steps to my system - LETS be safe
1 Look around - be aware
2 Escape and avoid - leave the area safely
3 Talk - rise hand, talk calmly,ask question, apologize and leave
4 Stun and run- when everything failed, engage and go home

Self defence is not about staying there
so many cctv vision has 1-2 minutes of threatening pre fight contact followed by 17 seconds of fight time
in the first minute dont stand there, dont just move one or 2 metre while he has another go at you
For your SAFETY leave dont argue, call him names or swear at him simply leave

if it continues verbal fence them in a loud clear voice tell them to back off while you back away and go home

Be smart, be ready and be safe