so by the power of the SEARCH button I think I've answered my first question which was:
why wont my TiVo play nice with my 172.16.x.x subnet?
...appears to be a 192.168.x.x or nothing!
second up was Will plugging TiVo into my LAN change my life?
again SEARCH seems to say NO, it just allows you to use your tablet or phone as a remote control (you still need the telly attached to the TiVo to watch anything)
can I connect to the IP address displayed on my TiVO? and do anything worth while?
I've always been able to search the guide and book recordings via the TV Anywhere app (no internal connection required), but I was thinking I've been missing out on features and so tried to hook the TiVo up with no success
Has Virgin Media provided any sensible reasoning for the bizarre decision to only support the 192.168.0.0/16 addresses ?
It does seem a somewhat questionable decision for Virgin Media to allow their home hub to be configured in a way that is incompatible with their other offerings. Most of the forum discussions seem to have descended into unnecessary bickering now, with more poorly informed speculation than fact. It looks to have been an issue for a number of years now, so I don't hold out much hope of a fix being released.