Thread moved to internet discussion as you are still seeking information on the Virgin Media National product i.e. ADSL.
Unless this is an area where there has been a LLU installation by Virgin Media, i.e. they have connected their own kit in the BT exhange, which is quite rare, VM's ADSL will be limited to the speeds of the BT up to 8 meg product. Try
http://www.samknows.com/broadband/broadband_checker for a guide.