Thanks for the help so far.

Tonight I have:
1. Downloaded the image on to the HD - a friend of mine had an old Pentium3 which worked fine!
2. Placed this in to my Tivo.
3. Installed the cachecard with the 512MB RAM.
4. Plugged the Tivo in to my TV.
5. Started up, went through the on screen instructions, and it works!

I am having a couple of problems though:
I have a Pace Sky decoder which is plugged in to my AUX socket on the back of the Tivo - but for some reason Tivo doesn't see the Sky signal. I tested the signal to the TV, and it is OK. So I have had to revert to using the RF cable for now.

IR Blaster - When I test this, I change the channel and lose the picture, therefore having to go back to the RF section and manually changing the channel back to 38 to pic up the sky. Any ideas?

The Tivo tells me I have up to 900 hours of recording, yippee!

Ian