Can female staff enter men’s changing rooms while customers are undressed?

I was the only one in there and was naked
In the shower Washing my hair when i heard a voice which was not male. I looked up and there was a female in her 20’s looking at me asking if I minded her cleaning as it was time for her to go home and her dad was waiting outside to give her a lift! She was just standing there waiting for me to respond grinning and looking me up and down and said “Dont be shy I see guys naked on a daily basis in this job” I told her she should not be in the mens room and that if a male walked into a female changing room he would be in big trouble! The only response I got was “If your shy put your hand over it”! Bit too late by then! I am body confident so it didn’t bother me too much but it was the principal of the matter so as I left, I spoke to the general manager who unfortunately was female too She asked me if the girl shouted she was entering to inform customers of her presence. This has happened on a few occasions since. What should I do? or am I just being prudish.
The same thing Always happens in McDonald’s When I have a pee👀🤭
Also there must be a safety issue for a young girl on her own walking into a room full of naked men!!!
Can female staff enter men’s changing rooms while customers are undressed?
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