There certainly are ways to re establish single sex spaces for women. It would involve, say:
Making very clear that a space labelled for female single sex meant female only. (The amount of panic and rage that appears on twitter from certain lobbies in regard to any suggestion of this demonstrates its power.)
Ensuring that single sex spaces are available and labelled alongside mixed sex provision, and where necessary the mens provision becomes the mixed sex one.
Holding a public awareness campaign about the vulnerabilities and needs of women for inclusion and access, particularly groups with protected characteristics.
Putting up notices about the importance of care and respect for all groups including women, making the expectation clear.
Empowering all business owners and public spaces to contact the police and report if a male has invaded a female only space and refuses to leave when inclusive provision for them is available. (Again, the mens should be made the mixed sex space if space does not permit a third space.)
Prosecutions if necessary for those very few male people who would determinedly and intentionally enter designated female only spaces with the intention of meeting their own needs and wishes at the expense of the women there needing a female only space.
Basically the TQ+ campaign strategy, but this time looking for solutions that would work equally for everyone as opposed to trampling one group underfoot.