I just recieved a call from a Virgin Network Engineer.
After being told "I cant prove im having the problem and its impossible im having the problem" another modem acting like mine was witnessed in Swansea just up the road on Saturday.
I have also recorded my problems for "Proof" and uploaded them to Youtube and they have seen it and admitted its the same problem and a problem with the BSR where its not assigning IPs properly to some modems and must be a config error as its only giving out 24hr leases to some modems and then dropping connections when they r up like mine.
Here are the vids...
http://www.youtube.com/watch?v=i_wop8jMhKI
http://www.youtube.com/watch?v=Q-N-4rZ37QQ
This one shows the modem a few mins later than the video above locked on but still unable to get a connection to the internet.
http://www.youtube.com/watch?v=xganVqIP9Ec