"...but since "the law is always speaking" that's not a slam-dunk that a court will see it the same way at the end of 2025, 32 years later. A lot has changed in 32 years."
Even though much has changed in 32 years, the "always speaking" principle doesn't change a concept. Although it may change what is included in that concept.
For example, if Parliament, however long ago, passed an Act applicable to dogs, it could not properly be interpreted to apply to cats; but it could properly be held to apply to animals which were not regarded as dogs when the Act was passed but are so regarded now.
(That analogy is from a House of Lords judgment back in 2003).
But you cannot construe the language of an old statute to mean something conceptually different from what the contemporary evidence shows must have been intended (from a House of Lords judgment in 2000)**
Even before FWS, it was acknowledged that there was a difference between those with a GRC and those without.
The correct comparator in a discrimination case involving gender reassignment for a trans-identifying man that did not have a GRC, and was therefore legally male, was always a man who did not have the PC of gender reassignment.
Men without a GRC were always conceptually different from women (I would argue). FWS was about whether men with a GRC were also conceptually different from women.
I would argue that back in 1992, the "concept" that they had of men and women was simply that of biological sex.
To now try and argue that the word "women" used in the 1992 Regs includes a group (men) that is conceptually different from the ordinary, accepted, meaning of “women” even nowadays, let alone in 1992, I would suggest is not likely to go anywhere.
Just my thoughts though.
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** This is just me going totally off tangent about not construing an old statute. This was a very mundane case indeed that made its way to the House of Lords.
It all revolved around whether Mrs Oakley's landlord (Birmingham City Council) should have provided her with a basin in the WC under the Environmental Protection Act 1990.
The then current Building Regs when the house was built didn't require a basin in a toilet. But Mrs Oakley claimed that this made the house unfit for human habitation.
The House of Lords went back to the Nuisance Removal and Diseases Prevention Act 1848 which the 1990 Act followed on from (and even earlier temporary emergency legislation from 1846) to understand what the 1990 Act meant and decided that the requirement for provision of a basin in a toilet was something totally conceptually different from what was originally intended.