One of the problems I wasn't expecting to have with them, but I do, is to do with my mother. She has fairly advanced dementia and there is no way we can let her lock a door any more, it's just not safe. So, in the classic single-sex loo arrangement she goes in and the door gets pushed shut and I stand outside (holding it closed if possible but if not, well, everyone understands) and just let the other women there know she is there, and as I say everyone understands.
The mixed sex ones we came across were at the John Radcliffe hospital in Oxford. They're actually really well designed for almost all situations - they have groups of them, where there are single-room loos (including their own basins) some of which are set up for additional needs with assistance bars and so on, some baby-change ones. They're even not tucked away in dark corridors - they're not areas where people are going to lurk looking suspicious.
But that last point made them difficult for our particular situation, because if the door had floated open it would have been incredibly public and embarrassing for my mother. So, we always had to go to the extra-access or baby-change one in any block so that there was room for two people in the cubicle, and my mother had to put up with me being with her - which wasn't exactly a problem for either of us, but it's a level of invasion of privacy that she doesn't usually have to put up with. She has dementia sure and can't do locks,. but she can still pull her own knickers up and down, for fucks sake. Except in the John Radcliffe hospital.
It just felt really sad, if you know what I mean? Hospitals are stressful enough without all that.