That doesn't work. It was whined a lot when places were told they had to create accessible entrances and toilets for disabled people. That was done and dusted in about five years, through government and local authority programmes, funding available, inspections, regulation that all new builds must evidence this. The blueprint exists, it would be easy. Disabled people incidentally didn't whine and pout that this took time: they'd spent decades fighting and knew that change in progress was a good thing. Which is rather different to 'if I can't have it right now I'm snatching your space off you and I don't care about anyone but me'.
There are many, many females who express their ability to share intimate space with male people, who have been lucky enough not to feel they want or need single sex spaces. The obvious answer is to remove some sexed space from both existing provisions, create a gender neutral one AND two smaller sex based spaces. That's inclusion: no one excluded because of their needs.
Then you come to the actual crunch which would be trying to get some male people to respect female need for a single sex space and their equality of inclusion, and not to target that space and the non consenting females in there in order to meet their own emotional needs.
That's the bit that would truly be the difficult one.