The Reply from the UK Registrar of Births:
Thank you for your recent communication concerning your birth registration.
The birth register in England and Wales is an historical record of a birth rather than one of current identity and the law only allows the Registrar General to authorise a correction to the statutory record if she is presented with evidence that can confirm that an error was made at the time of the registration.
When someone is alleging that they are not of the gender that was recorded for them in the birth register we would need to be presented with medical evidence to that effect.
As we are not medically qualified we would then in turn refer the matter to our medical advisers to see if they are satisfied by the evidence that an error was indeed made at the time of the registration.
I would also add that corrections can only be carried out in the way the law prescribes by means of a note in the margin without alteration of the original particulars upon receipt of statutory declarations made by two persons with first hand knowledge of the facts of the case.
In a case such as this one of the declarations would have to be made by someone medically qualified the other by the original informant of your birth, normally your mother or your father.
In your first mail to this office you made reference to the Gender Recognition Act 2004. As you may know when a transsexual person is issued with a Gender Recognition Certificate the Registrar General must create a new record for that person in the Gender Recognition Register.
I appreciate however that you may not consider this to be appropriate to your particular condition.
If you send any papers to this office they would have to be original documents and they should be sent to:
PO Box 476
The reference number (REDACTED) should be quoted in any correspondence.
I hope this is useful to you.
Interesting. An official statement that the UK BC is of historical value only, and does not necessarily reflect current identity.
Of course the reply doesn't actually help me, but they did their best, and I'll be sending my sincere thanks to them.