i don't mind too much about mixed changing rooms so long as there are cublicles but then i like cubicles in female changing rooms too. the trend for communal changing rooms seems to be going away in shops and so on. But toilets are a different thing. I hATE mens toilets. 9I have been known to end up there accidentally or deliberately if it's an individual one at the doctor's ot something) I just find mens and boys toilets too smelly. - sorry guys! disabled toilets tend to be diferent because they're not used as much.
As for a third changing room, - I don't know. There would need to be a forth if we go down that route - male, female, transmale and transfemale but what about people who don't want to openly declare themselves trans?