Just this really.
Attempts to alter your body either surgically or chemically will not alter the law as it now stands and it should be made clear hormone intake of surgery cannot alter your biological sex.
I just worry that extreme transitioners will use any attempted body alteration as a reason to question the law as they will attempt to say the alteration in some ways make a then 'biological ally female'. I worry fake breasts for instance may be used to 'muddy the waters' with this legal clarification and there will be an argument that for instance addition of breasts and removal of a penis (in an extreme example) will warrant challenge to law.
I have a fake vagine=woman could add dealt difficulties possibly in terms of law as it then becomes the responsibility of an individual institution or group to prove biological birth sex to respect the law and this may be a challenge in realistic scenarios.
Will full transitioners act as a test cases for this new interpretation of the law?