Any fight you can walk away from is a win. Anything can happen. I avoid them, too many things can go wrong.

However, you mentioned "poportionate response" in the context of your actions.

Is there no UK legal concept for "disparity of force?"

3 assailants armed with impact weapons would seem to negate your needing to estimate what is "proportionate" force for your self defense.

How could you judge their ultimate intentions with any certainty? You can't. "Proportionate force?" To being outnumbered 3 to 1? They with impact weapons and you only with your hands?

Once the 3 made the threatening and furtive movements towards you all bets should be off. You have no idea what they are planning or their actual capabilities.

Sorry for the long wind up here, but I what I am asking is
there any British legal concept of "disparity of force" viz a viz being attacked by muiltple assailants and actions for ones self defence?