We don't have 'staff' toilets as such but open blocks with disabled toilets (large loos with wash basin etc inside) which only staff or kids with a key card can use. This is literally a non issue. I have never heard anyone complain about it.
All the student toilets are open blocks, set just back from the corridor. Unisex but full length doors, shared washbasin. Again - no complaints and no real issues. I remember kids smoking, fighting, bullying and vandalising in the old style girls and boys toilet blocks. We get none of that at all.