This is the day my replacement Superhub (which was initially running the older software) upgraded to the new software at around 3:45 am:
While this isn't affecting everyone, it appears that this issue is widespread enough to require some attention from Virgin Media. Can someone from VM please respond to this thread to let us know if VM are aware of this, and what action is being taken? Is there any chance of getting software rolled back to the previous version?
Power off the hub for 5mins if you have your own router copy it WAN MAC to your PC NIC and only connect that to the hub and power on (unplug and replug the ethernet may be needed) see how your connection is for some hours.
In modem mode, as the thread I linked says (hopefully).
Done many tests with different equipment connected directly to the hub. Haven't gone as far as duplicating the MAC address though. All the tests I've done show a similar result. Running in 'router' mode isn't an option for me really, despite one of the support line bods trying to tell me that modem mode isn't really 'supported' by VM.
As I said above, I'm not alone in this, so troubleshooting my setup would seem a little pointless. While it's not everyone with this hub software that is seeing the issue, there are a number of people reporting it on here.