The fix, (rather major), is as follows:
- Go in to device manager, and uninstall all USB devices (including USB root hub)
- Unplug the cradle & SPV
- Uninstall ActiveSync
- Reboot in 'Safe Mode'
- Go in to device manager, and uninstall any other USB devices that appear
- Install Activesync
- Plug in CRADLE ONLY
- Press 'Next' on 'Get Connected'
- Plug SPV into Cradle
Voila, problem solved!