"The GRC law changes your birth certificate.." Strictly speaking, I think a NEW one is issued, and the link between the old and the new kept in a register, access to which is restricted. I think, similarly to the Kim Walmsley case where a clerical error recorded her as a boy, the ORIGINAL cannot be destroyed or amended, even if incorrect, instead a replacement and a note of WHY there is a replacement has to made. The records entered on the register cannot be erased or amended directly, just replaced. The record IS the record!
As regards this case (and the recent trans prisoner from Bristol), as far as I know, NEITHER of then had applied for a GRC (where the relevant panel has to be shown some sort of evidence of your 'gender' identity). Hence the current furore, is accepted, would in effect be -- someone HAS a female gender identity (and hence goes to a womens prison), if they SAY they have. No convincing a panel required.
Why? Why after all, do we house males and females seperatly? If BIOLOGY , then self-identification means diddly. If BIOLOGY, then a transman with only top surgery, despite the best response to T going will still tend to have a smaller frame than a male, and be vulnerable to being raped in a different way to a male, and still possibly in danger of pregnancy (transmen have given birth, we saw the news!). There are apparently exceptions possible under the act for SPORTING events (except the case of the trans woman cage fighter who did SERIOUS damage to the female fighter who came up against them!), so why this insistence that in PRISONS, subjective beliefs should come first? YES, make proper allowances for vulnerable prisoners, but WHY should the rights of females to be housed ONLY with females be ignored?
I might just add , in the US, there are several cases of male rapists and murderers claiming they are trans and trying to get (I assume), both SRS and transfer to a womens prison. DO we REALLY want to see the possibility of that in the UK?