You do not have to say "yes" to this gotcha question to be allowed to have female only changing .

Single sex services are not going to suit everyone. Some people "don't fit the binary"

Stores can provide a unisex option (or convert the men's to unisex ) https://twitter.com/AdrianHarrop/status/1263515711739252737

Trans pple have a right to privacy: u can't ask about surgeries etc...hence Jamie can't use the ladies because it wld require explaining to the other users.

Jamie is perceived as a man & discrimination based on perception is included in Equality Act (so part of the exception)

Single sex spaces work for ppl happy to declare their sex & who haven't undertaken body modifications to try to look like the opposite sex.

Instead of trying to squash people w gender dysphoria into spaces that dont work for them, provide a unisex option for everyone's privacy