Ezra, thanks for that but I'm still confused. You say that after Foxying, the Humax treats both HiDef and SD as the same - in which case why do only the SD files show up when I try to play them via the DLNA server? Neither Windows Media Player nor XBMC can see the HiDef program. I appreciate that in order to play the files "directly" from a drive (or for example to FTP off a clear copy) then I need to USB copy the file (off and then back) but I thought that I didn't need to do this in order to play via DLNA.
Also, I know the IP address, but how does this tell me the URL of the file if uPDP is not working? This is probably blinding obvious to you but not to me

. I'm expecting to have to type something like:
http://192.168.0.221/my files/video/torchwood/2011-01-10 Monday.ts
...but what are the actual protocol (http), directories (my video etc.) and filename? Can I determine this by using FTP and then perhaps changing the protocol that I give to Windows Media Player?
Umm, as I type this I'm wondering if the HiDef file is not recognised because it is using a different video codec to the SD file - do I need an add-on for Windows Media Player?
Thanks,
Papadeltasierra.