I shall close by answering the last 3 posts:
Celstialspanking 
"My local Tesco has signs all over telling us to not abuse their staff, never had those before. Having worked in retail for a good decade or so previously I can only imagine how shitty some customers have been the last however many weeks."
I didn't abuse her, I apologised. I explained, as she shrieked at me to 'get back!' (but not 'back' away from her, but 'back' outside the store, (as she, hidden... had not 'invited' me in) and in doing so, was demanding I walked a) back towards her, b) towards the people exiting the store, and c) the person who had stepped forward into my place in the queue. I was not 'shitty', I apologised, telling her I had not seen her, hidden as she was. In a place no other queue manager had stood (as the others stand outside). Which was what her co-worker, clearly suggested to her, right then, that ' In this lovely weather, I like to manage the queue from outside' hint.
Emeeno
"Have you ever reacted to a situation badly OP? Ever snapped or spoken sharply? We all do, this woman is just as human as you.
I know when I feel embarrassed or humiliated I feel angry which leads me to interpret others behaviour as worse than my own. Maybe that is what happened here."
No, I didn't 'interpret' her behaviour as worse than my own. It very clearly was. I didn't disobey her as she was not visible to disobey.
Pingu
"It sounds as though you've blown this all out of proportion. It isn't 100% clear from your opening post, but maybe you walked into the store before the customer you were replacing had fully left?
These are difficult times. You, being on the front line should know this. This incident really isn't worth so much anger."
No, I walked in as one left, as there was, apparently, no one managing the queue. These are difficult times. I, on the front line know this. Believe me, I keep Social Distancing!
Which is why I am perhaps less forgiving of the way this store assistant behaved. She shrieked, while lunging forward, she humiliated me. Everyone looked, and, you know what, after my shifts, where I'm thinking, in my PPE 'Fuck, fuck, fuck, fuck'- why is no one suggesting she might not consider my position?
Or, in reality, could it be that despite all our pretty MN words about 'equality', as she is a 'mere shop worker', we can consider her incapable of considering the affect of her words, and actions on others thus is forgiven. But the HCP, hurt and humiliated by her actions -should reflect. As she is 'the bigger person'.
Which is it to be?