Lots of new build schools have toilet blocks designed such that there are individual 'private' cubicles and then a publically visible sink area - not unlike the arrangements in many public places (service stations, shopping centres, venues and so on - Manchester Arena is one, from memory) that I've been in. Some schools removed the external doors from pre-existing blocks to improve ventilation, due to covid, and apparently some have done so to address anti-social behaviour., although this hasn't happened in any of the schools I work in - I think that they did chock doors open in some cases for ventilation. The legal minimum provision is, from memory, one toilet per 20 pupils, across the whole school site. If these are provided as separate girls and boys facilities, a urinal can count as one toilet for the boys, although at least one third (again, from memory) of the required number should be provided as a toilet, not a urinal. Staff toilets have their own minimum requirements, and should be separate from pupil facilities with the exception of accessible facilities which may be made available to staff, visitors and pupils.
In Barney in 2013 (so at the comp, not the indie) if I remember rightly, Phil Dyson made the very pragmatic decision to designate all staff toilets as women's and all pupil toilets as men's, since he'd calculated that the ratios should work out about right that way given the gender split of participants.
I'm kicking 50 now, and when I was in secondary school remember that most people would avoid using the school toilets if at all possible, because they were all a bit grim. Some things aren't new...
