It seems it's a stupid restriction in the TiVo IP address settings.
Initially, I hadn't realised the box needed to be connected to my home network (duh, its connected to virgin cable right?). When I plugged an Ethernet cable in (who has one of those these days?), I got "There is a problem with your network settings. The specified address is outside the range of allowed IP addresses (C138)".
Usually when connecting the TiVo up via an Ethernet cable direct from the Super Hub, the Hub automatically assigns a 192.xxx ip - this should allow the TiVo detection for TV Anywhere online.
Any other range of ip address outside of this may not allow the TiVo function you are trying to access. I can see on the link you provided that another customer advised he set a 10.xxx ip and his TiVo then showed online for TVA.
If you are unable to pick up a 192.xxx ip address, factory resetting the Super Hub may be needed.
Let us know how you get on with this.
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