I've had similar issues. I got the email saying I was upgraded on Friday, Saturday I had the connection drop a couple of times then Sunday it went completely and would come back for a couple of hours at a time. When it goes down the Superhub goes to a green light with two arrows flashing. I use my hub in modem mode so the wifi isnt even in use. 2/3 of the people I know on Virgin media have been having similar issues wince friday and they arent even in the same area as me.
I have tried a pinhole reset on the hub etc but its still the same. I have aan engineer coming out Thursday, looks like im using phone data until then!
***** If you think my answer has helped - please provide me with a Kudos rating and mark as Helpful Answer!! I do not work for Virgin Media - all opinions expressed are of my own and all answers are provided from my own and past experiences. Office 365, Dynamics CRM and Cloud Computing Jedi