Is the positive feedback because the new facilities are mixed sex or because the facilities themselves are simply better designed? I suspect the latter, but please feel free to explain why the mixed sex element is pivotal to the positivity.
I'm really not getting the "mixed sex" emphasis here.
The toilets are better designed. That's a fact. The improvement is that they are private and open directly onto a main corridor and so eliminate any potential for bullies to congregate there.
I'm not sure how we could offer the same but one set for boys and one separate set for girls. There's not another place in school that provides the same opportunity for supervision and they were expensive to build. I don't consider them mixed sex. Sure, a boy might use 1 while a girl uses another but neither can hear or see the other and they aren't enclosed anywhere together.
I have no.knowledge of any school that has implemented mixed sex toilets using any other design than these tbh. I wouldn't get on board with an old style single sex toilet block being made mixed sex eg a large room containing multiple cubicles now being open to both boys and girls. That removes none of the ranges of single sex toilets ie opportunities for bullying and just introduces many more dangers but the new designs that I've see. I think are a huge improvement.