Hey Beckster hon!
Pleased to see you again.
The Data Protection Act 1998 places duties on the employer and gives rights to the employee on the control and issue of data. As you have found one of your rights is that you can ask to see all of the data an employee keeps on you during your period of employment.
http://www.ico.gov.uk/what_we_cover/data_protection.aspxOne thing an employer cannot do is go back and change past records (prior to your name change) as this is illegal, they can not also give your details to any Company or third party without your consent. If they have done that they are in breach of their statutory duty.
If you think they have breached any of your rights or their legal duty then contact the Department of Constitutional affairs.
If you have A Gender Recognition Certificate under the Gender Recognition Act 2004 (and a re-issued Birth Certificate) then you are further protected for Data Protection as any Company and Government Organization has to archive your old records, so that their is no link between old and new gender. and again no one can release these records without your written consent.
Section 22 of the GRA 2004 defines this
http://www.opsi.gov.uk/acts/acts2004/ukpga_20040007_en_1Buffy
All of the above do not apply if you are undergoing a Police Investigation or are a registered sex offender!!!