The keyboard is clear plastic with white keys, not the clear and black I've been using, which is more in keeping with the computer, the plastic of the mouse and speakers seems virtually unscratched, etc. etc.
I forgot to say that it also turns out that there was nothing wrong with the other keyboard - I noticed it wasn't working just after plugging the USB blutooth pod into it, and somehow missed the obvious conclusion, some sort of clash. It worked fine with the bluetooth plugged into another USB port rather than the keyboard's sockets. I really don't need another Mac keyboard so I'll probably flog it once I'm sure everything is OK.
Now just the other 512mb to come and I will hopefully then have a state of the art computer... for 2005-ish. But certainly good enough for DVDs, web browsing, etc.