Admin Gender in PDS

Good morning,
Quick question on Admin Gender and changes to it.
The FHIR API docs indicate we CAN update admin gender, there’s no specific restrictions on this functionality listed and I don’t think there’s anything listed in the SCAL to the effect that we shouldn’t update it.
However the guidance for gender reassignment seems to suggest that only GPs should be triggering this (and even then they don’t look to be altering an existing record, instead creating a new one).

Can I clarify if there are any restrictions/guidance on how this update is used?

Also is there any specific clear guidance on Admin Gender vs Birth Gender vs Gender identity (realise this may be a changing area at present)?
I.e. best practices on what should be stored and what can/should be inferred from admin gender (i.e. if an unattended PDS lookup as part of an ERS flow registers a previously unknown patient should we infer birth gender, gender identity etc from this or be prompting user clarification at a later point?).
For context this is largely driven by trusts saying that downstream system want gender at birth/biological gender. Clear guidance on exact meaning of admin gender and what we can do around it would be useful to inform discussions.

Thanks,

Liam