In a class with unequal numbers of 'boys' and 'girls' (however you define such terms) there will be some gender swapping, more a position in dances. DD goes to highland dancing, the reel was originally gendered roles, but as 95% are now girls this became meaningless.
Changing is a bit more complex. Usually trans pupils are given separate spaces, thats how DDs school handle it.
Not worth a song and dance about. 