Thanks.
Yup - that worked. A little more investigation and it looks like it's the same web interface that TiVo has had in the US since Series 2, but with all the shows currently 'Protected' rather than letting you download them. I would guess that's something to do with the ongoing rights management issue that prevents multi-room streaming from working.
You can also get an XML view of the list by going to
https://x.x.x.x/TiVoConnect?Command=...ng&Recurse=Yes - replacing the x.x.x.x with your TiVo IP address. As a coder, that could be an interesting feed to use once (and if) VM allow shows to be downloaded directly from the box.
Pete