I finally managed to drag the computer away from my wife last night and post in the VM newsgroups.
Was quite late so no reply by the time I went to bed, but just logged onto the My Virgin Media pages and it says 10Mb M

whereas last night it still said 2Mb M
Have to see what I get when I get home, can't get newsgroups here at work, so see what they say about a new modem, currently got the ntl 120 modem.