This is taken from Trans Media Watch here, and is part of their advice to the media on reporting incidents involving transpeople:
When a Gender Recognition Certificate (GRC) is awarded, it becomes a criminal offence to reveal the owner’s transgender history. At present the fine is £5,000. It is the individual who reveals the name, not the organisation for which they work, who will face charges. There are no exemptions for journalism as there are with the Data Protection Act. Section 22 of the Gender Recognition Act was created with an “expectation of privacy” in mind.
It is important for a transgender person to be able to wipe the slate clean, to live a life free from persecution. Provided they have no outstanding debts, their credit history will be erased. They will be entitled to a new passport and driving licence. There is even a fresh birth certificate to help them through life. All of this is to no avail if their previous and current name are linked on a website. When this happens, such a person has no choice but to change their name again if they want the privacy to which they are entitled.
Whilst the legal position is not cut-and-dried, it is heavily weighted in favour of the transsexual person. Even colleagues discussing a post-transitional person may be in breach of this law. Even before the award of a GRC, charges of harassment may be applied if the person is reported about on separate occasions using their previous name. Any article remaining on the internet following the award of a GRC may expose its author and editor to risk of prosecution.
The award of a GRC is never publicly announced, of course. There have been no high-profile prosecutions under Section 22 but that situation is unlikely to last. It is best to respect the terms of the person’s deed poll and refer to them by their chosen name only.
Clearly this makes it possible for people to 'relaunch' themselves, much like changing a user name online, and in most cases that will be a good thing; but equally clearly it gives scope for people to separate a nefarious past from the present. This is not to imply that everyone changing identity is doing so for nefarious reasons, but the fact remains that it is another example of how 'the most marginalised group in society' has rights that are not afforded to the rest of us. If I committed a crime, the names of my children could be published, as well as any previous convictions I had, places I had worked etc, and it would be much more difficult for me to put the crime behind me.
If these things remain private in the case of transpeople, it stands to reason that the differential between the law as it protects them and the way that this protection does not protect others will encourage some criminals to pretend to be trans in order to deceive.