The entry in the Registry comprises the first three letters of the applicant's surname, the first five letters of the first name, the date of birth, together with the date and codes for the relevant insurer and the type of policy.
So If my name is "MICHAEL GOLDSMITH" and I share a birthday with a deeply unhealthy "MICKEY GOLDSTEIN " I can be turned down for life insurance because of him or his policy history. Not only that, if I make a data protection act request I will be given his information....
The really bizarre thing is that the Data Protection commissioner is aware of this but doesn't seem to find it odd...