I would question whether TWAW would pass the Grainger criteria in section v, either. It seems incompatible with women's dignity and definitely conflicts with our rights. And is it really WORIADS?
I don't know if it has been explicitly stated by a judge that TWAW is a belief that is WORIADS, or if it is just taken as a logical consequence of a finding that a belief in the binary nature and immutability of sex is WORIADS, and therefore disbelief must be, too.
I can't get away from the empirical aspect. The belief that TWAW is predicated on 1) the belief in the existence of a gendered soul or essence (GI) and/or 2) the denial of a material reality, or the idea that that material reality doesn't matter or can be altered by fiat. The first and last of the ideas in 2) can be disproved conclusively, the second one is just an opinion.
TWAW is different to religious belief. For example, the fundamental tenet of all the Abrahamic religions is that God exists. Although I personally don't believe that God exists, I can't prove that he doesn't. I might be able to point to inconsistencies or contradictions in teachings, errors in translation etc, but I cannot disprove the fundamental tenet, because it is not a belief about a material reality. It's faith. The belief in gendered souls, on the other hand, is of the same type as religious belief. So I think it passes - just - the Grainger test. (To the religious amongst us, please don't be offended by the comparison - I am not implying that GII has the same standing or any value for society as a whole.)
A belief in gendered souls means you believe that there can be such a thing as a woman in the body of a man. The belief that TWAW is that the male body is therefore a female body. This can be shown to be untrue. If the definitions, properties and measurements relating to body/sex/female etc (the established understanding) which are used to show its falsity are decried as wrong or outdated or something else then TWAW itself becomes irrelevant to policies around bodies and sex and women's rights. Because those policies are based on that established understanding of what bodies/sex/female/rights etc mean. So of course anyone is free to believe that TWAW but I don't think it passes part v of the Grainger test. It is a demonstrably false belief and I don't think that category of belief should be protected. The Royal Family are not lizards. Men are not women.
IANAL and I would love to see this tested in court.
If it already has been, apologies for wasting your time! 😂