Learning we were losing our Tivos was a sad day. The alternative machines didn't look that great by comparison, the WAF wasn't great and it pained me to have a functioning machine that was essentially likely to end up as landfill.
But there was hope on the horizon. The OZ / NZ tivo community have been working hard at finding a solution. The solution is now out there and it works!
So after all this angst I would like to publicly thank Skolink and Darren for helping me through this process. I don't know a RAM from a motherboard but at least I know what a HDD is. They helped this newbie work through the issues I came up with so that I now have a fully functioning Independence Day version of tivo up and running.
Of course my thanks also go to the generosity of the whole local Tivo community who have worked to make this possible. Such clever people out there giving their time and technical knowledge to the wider community. They have created a process that really is quite simple - fact is if I can upgrade my Tivo anyone can.
True legends. Thank you all!