The whole entirety of Plaid are slippery. I have never voted for them and never will. I, too, am politically homeless at the moment, and unsure if I will even vote. If I do, well, I am now a single issue voter: adult human females' rights. Whoever stands firm for those would get my vote, but I don't believe a single thing any politician says. They will say anything to get elected.
If we don't have a firm commitment to biological truth, then we cannot accurately define any of the problems we might want to fix in society- not women's employment rights and pay equity or childcare (all of which go a long way towards bringing women into the workforce and improving our economic stability), not women's healthcare (which will save the NHS millions as women age and live longer, ditto social care), not disabled women's rights to same-sex intimate care, not retaining female teachers in a time of rampant misogyny... on and on and on.
We have our female rights enshrined in law, which were confirmed last year. If the current or next UK government wants to start trying to dismantle the Equality Act 2010, then that will be a fight we will have to take on.
Until then, my strategy will be to be ready to take every single breach of my same-sex rights to court. Yes, it might be expensive, but we have the law on our side! (don't forget JKR's fund, as well). All they have is feelings, political clap-trap, and the hope that they can do whatever they want and no one will notice. They cannot win everything. And every win for a woman is a brick chipped away from the wall.
Legal proceedings are the only thing that works right now. Don't wait for your politicians to do the right thing. They will only ever do what is expedient.
I know this sounds idealistic, but it's clear to me now that we will have to sue. Every. single. time.