@DomesticatedZombie
The protected characteristics are separate and distinct. Being a trans woman explicitly does not mean you also hold the protected characteristic of being a woman.

In light of this, I think it's time that the mantra TWAW is retired. It should be banned from being uttered anywhere.
Incidentally, I found this & thought it was worth posting so people could see how the Scottish Parliament could get it so wrong - 1st link is to a session at Stage 1 of the GRPB bill with a representative from Engender & Women 50/50. Talat Yaqoob was a big part of why the GRPB bill came into existence & she outlines in her session how she (note - not women in general, but she/women 50:50) supports the Equality Network's position on ensuring that mechanism to improve women's representation doesn't exclude males who self ID as women Link to Scottish Parliament recording - it's at approx 38 1/2 mins in.
Following on from that, here's the session with James Morton of STA giving their stance on the bill, asking for a specific definition to be included so as to not place any barrier on males who self ID as women, but also to exclude females who don't ID as women. Link to Scottish Parliament recording - starts at about 6 1/2 mins, and at 9 mins, that's where JM lays out the requirements of STA to have the bill specifically include males who self ID as women, but exclude females who don't ID as women.
What JM/STA asked for was pretty much what they got, which we now know was unlawful. But, as is the way with Scotgov, they simply acquiesced instead of actually checking the legality of this (or did check but still thought it was arguably feasible).
I think that it's also worth highlighting that, in the 1st round of the legal challenge, En/STA were given permission to intervene & part of that included statements from males who identify as women, on how they were intending to apply to join a number of public boards. The mechanism that STA managed to get included (unlawfully) in the bill was the vehicle for more males to join boards, at the expense of opportunities for women. I can't tell you how delighted I am that this gerrymandering of women's rights & legal protections (especially in mechanisms to encourage more equal female representation) has finally been halted.
Cheers to FWS🍾🥂