OK, now to answer (at least in part) my own question.
XP64 recognises the keyboard but I haven't yet installed the software as I wanted to be sure it would pick up the controller first!
Strangely, it doesn't work on my 32bit XP, even though it shows up in the device manager with no warning symbols to say there is a problem(?) I hear there can be problems with things like webcam drivers knocking out the generic midi drivers in windows. Does anyone know how to get around this?