Hi dcclanuk
I've managed that. You need a RF demodulator (this is the one I got), plugged into the tivo scart socket then plumbed into your RF distributor (i assume this is how you get your tv to your upstairs room, it's how i do it)
http://www.amazon.co.uk/dp/B000M6SMK...&creative=7966
Then you need a infra red extender to pass the signal to your tivo from the upstairs room so you can control the tivo remotely. One extender in the room you're in, the other in line of sight of the tv box. The link below is for the one i use. It works well for me.
http://www.amazon.co.uk/Marmitek-Pow...ol+transmitter
hope this helps.