Strangely someone asked nearly the same question yesterday. Read the posts from here onwards
http://www.cableforum.co.uk/board/11...l#post35750777
As for relocating a TiVo, an extra 10m cable isn't a problem at all if the job is done properly. Best to get Virgin in to do it. (They would relocate one TiVo upstairs too, if you wanted)
ps. Welcome to the forum!