I think you're talking about unisex single room toilets with a sink in the room, and floor to ceiling lockable doors? So the common configuration for a disabled toilet. A disabled toilet needs to be three times the width of a standard toilet to allow the wheelchair to be comfortably turned around.
These facilities are, of course, fine, and very necessary for people with a disability. But should be in addition to separate communal toilets for Men and Women.
Firstly, unisex single room toilets are very space hungry. Secondly, men do not always dress or zip themselves up fully prior to leaving. Thirdly, they are more likely to be abused for drug use/sex and so unavailable/insanitary. Most importantly, these cannot have the door gaps needed for safety should the toilet user fall ill.
Toilet refits are very expensive. UK businesses are already struggling. Why make such a massive costly change for a small number of people who cannot accept the sex of their own body?
One woman, or even a group of women, cannot consent on behalf of other women and girls to men being in their women-only spaces. It's not how consent works, thankfully.
Also it's the law under the Equality Act 2010. If a public space is labelled or advertised as being women or female only, then all men - including transwomen - must stay out. Their sex is, and always will be, male so these spaces are not for them.