It's a really simple fix:
# Plug the speaker into your pc using the micro usb (labelled service) port on the back of the speaker
# On the Bowers and Wilkins firmware update software (free to download from the bowers and wilkins website)
# If the speaker shows up on the software, click 'eject speaker' on the bottom left, this sets it back to the default mode and it should work perfectly from this point.
# If the speaker didn't show up on the software, try unplugging it and plugging it back in. Note that the speaker must be turned on in order to be detected. If this still doesn't work, try restarting your pc and trying again. Otherwise contact Bowers and Wilkins support.