Steve,
You are not the only one.
I was a victim of identity theft over 6 years ago and someone opened an account using my name at an address which I di dnot live at. Despite disputing this account and reporting it to Actionfraud the wonderful people at Virgin insist that the account was mine and that I had to pay.
I had numerous letters and calls with their debt collectors at the time who could tell by doing a simple credit check that it was a fraudulent account only stopped chasing me when I threatened them with legal action for harassment.
Now Virgin seem to have sold all of their "old accounts" to another company who BW Legal are acting for. I have provided them with copies of all the correspondence I had with Virgin's debt collectors regarding this and 6 months later have still not had any kind of response from BW legal regarding this.
All BW Legal care about is trying to extort payment from people and not what the actual facts are.
If you hav enever been a customer of Virgin I would suggest that you report it to Actionfraud if you haven't already. They wont do anything but the reference number they give counts as a crime reference number (I think). Actionfraud don't consider it a crime against you unles syou have physically lost money because of it. Helpful I know.