I own a business and have been trading through a .COM web-site for 6 years. It's just come to my attention that someone is using my company name but with a .CO.UK. I orginally bought both and thought I still owned both but apparently not. The .co.uk name obviously lapsed and is now being used to advertise my competition.
Somtimes depending on how you registered the original name and how long ago the new .co.uk name has been registered you may still own the rights providing you pay the arrears. They should have contacted you about the lapse, if they did and can prove it you have no rights; if they didn't then you have a chance- good luck