Thanks kay, tried the dongle in two PC's at work, both running windows XP, and they installed and worked fine!
Uninstalled mobile connect (this takes the drivers with it I assume), and tried a different usb port and it seems to work fine! I think the first usb port I tried is a bit knackered as my new nokia 5800 seems to have issues connecting to PC suite via that same port.
Anyway, I'm posting this using the dongle so if your reading then it's all okay (I hope).