I'm in two minds about this...
Daughter is in year 7. Toilets are mixed. The area housing the cubicles opens out into the corridor. The cubicles have either green or blue coloured doors; blue for boys and green for girls but this isn't signposted. Children are told on their first day which colour is for which.
My daughter hardly uses the loo at school (thankfully) but she will accompany friends to the toilet area if they need to go. No one in her year group have started their periods yet. She says she is uncomfortable if year 11 boys are using the loos at the same time.
I'm not sure what to do really. The school is an academy in a semi deprived northern town in England. Senior staff are young suited and booted car salesmen type blokes. Sorry that sounds judge-y but need to set the scene.