Final update
The engineer came out today and replaced my Tivo with the V6, in spite of my Tivo being downstairs and Hub 3.0 upstairs, it took him 30 minutes but a lot of that was going through the various VM menus with a CSA. He didn't need to fit any powerline adapters or anything, I am glad I got the engineer as he showed me on his Blackberry a series of green lights etc to show everything was working well.
I just hope that I can see an improvement from my Tivo, thanks BM's for any help you gave me.