There is, as anyone who's actually thought this through has realised, absolutely no way at all to separate out a sufficient degree of transition from no transition at all, nor to gatekeep which males enter female spaces. If it's any one at all then it's all. The End. (for females)
And as Arabella says, for some women, that single one lovely wholly transitioned TW is still male and will still exclude them from women's services or indeed any services at all. Hence the issue mentioned on several threads today where male service users have access to a male group, a trans group, AND a mixed sex women's group and can take their preferred choice. Women get one option only with no choice, and any who find the mixed sex women's group inaccesible get refused any service.
It's male supremacism. I'm not up for it. I'm not supporting this total lack of ability to see female people as equally human, take the slightest interest in their lives or voices or needs, while stripping out their provision to male benefit and patting the heads of the little sillies who don't see their lives should be revolving around their betters.
Who in this position would?
Trans people are welcome to do and be and access whatever services they like, have all the services, have a lovely time, go crack on. The only interest I have is that female people get equal access, consideration and parts of the world that male people haven't ripped away from them because they feel more important and more entitled.
That's nothing to do with being trans, that's to do with being exceptionally bloody sexist.