Three pages of comments and no one has thought to clarify what kind of help was offered? The article doesn’t specify. In my M&S the underwear section is not curtained off like some scandalous part of the store that must not be seen - it’s all lumped together with tights and pyjamas and socks.
The conversation could have gone: ‘hello, would you like some help?’ ‘Yeah we want to try this bra on’ ‘ok, I’ll just grab a colleague who can open the changing rooms/get you the correct size/do a bra fitting for you’.
I’m a big believer in single sex spaces for both women AND men, and don’t really believe that people can change sex, but this seems like it COULD have been a massive non-issue and because the article is so light on details - I suspect it might be.