From the 2021 census question "to provide the first official data on the size of the transgender population in England and Wales".
A total of 262,000 people (0.5%) answered “No”, indicating that their gender identity was different from their sex registered at birth. Within this group:
- 118,000 (0.24%) answered “No” but did not provide a write-in response
- 48,000 (0.10%) identified as a trans man
- 48,000 (0.10%) identified as a trans woman
- 30,000 (0.06%) identified as non-binary
- 18,000 (0.04%) wrote in a different gender identity
So if you assume that the 118,000 were confused by the question, a third of respondents have some kind of non-binary gender. If you include the 118,000, most trans people don't fall within the 2016 idea of a transsexual and don't identify as a man or a woman.
I don't think it helps anyone to pretend that trans means what transsexual did in 2004, or 2010 or 2016 but I do agree that laws need to be changed by parliament, not by general assumption or 'getting ahead of the law'. I expect this kind of examination would not be welcomed by advocacy organisations, but that doesn't mean it isn't essential if they genuinely want to protect trans rights.