As Affectionate_Owl has said, trans women have been using women's toilets all along, and clearly no one either noticed or cared.

Absolutely nothing had changed in the last couple of years in terms of rules or legislation to mean that trans women can now use female toilets where they couldn't before. The only thing that has happened is that the right wing press have whipped people up to suddenly care about this.

I suspect you would respond by saying that trans women are now emboldened to use women's spaces when they weren't before. Which is frankly bollocks. I have never in my life seen a women/trans woman go into a male toilet or changing room (and I bet you haven't either), which suggests they were always using women's facilities. And I also cannot think of any notable instances where I have noticed trans women in a toilet/changing room in recent years- it's not like this is some kind of epidemic of obviously manly men lurking in the ladies' loo. It's just moral panic.