An update: I decideded it must be something odd with the 30GB hard drive, so I bought another one off ebay. Installed it last night and it worked.
Was pre-formatted as FAT32 so it was just as simple as plugging it in and turning it on.
One thing I noticed is that the sticker on the first drive I tried was different from the second (the second one had an extra bar code at the bottom, and an Apple logo). The first was made in Indonesia, and the second one made in China. So maybe there is something subtly different about the Indonesian-made drives which means that the iriver doesn't recognisde them? Oh well, pleased to have an H330 at last!
