Had to reboot the router this morning to tidy the cabling, and when it came back up it wouldn't connect. Tried phoning Virgin - what a mistake that was. 3 x calls to their Indian call centre and an hour and a half later I had had two hang up on me and one being very rude.
I have a Draytek 2820 and it works fine. Initial problems were a little like this. Power cycle the cable modem (wait 30s or so with it off) as people told me it remembers the MAC address of the last thing connected. After I did that it all worked perfectly. I do not spoof the mac address. Let me know if you want any other help with settings.