I just did the same. Linkedin came up, and then fantastically 192.com lists my previous addresses along with previous occupants. This includes an ex, three people I shared university accommodation with, and fantastically my parents names: including my mother who kept her maiden name.

All those were done before I really understood opt-out on the electoral register, and my parents registered me without telling me. And I have no way of removing the information, despite the fact that mother's maiden name is still bizarrely used as a security question.