wodehouse? Did you try what I suggested above? It does work if you turn it on in the right sequence. Ha! Make a liar out of me if you can. 
ONSatan, it is odd what you report. You did not confirm whether you saw ‘Cubase (and the computer name)’ in the iPhone or iPad app when you turned on Cubase. What came up in the screen? If nothing, then you have a different problem I think. IF THE LINE ‘Cubase (and the computer name)’ DID SHOW UP, THEN IT HAS TO CONNECT.
So what did or did not show up?
You do know, it might be possible that the Mac OS is not releasing the connection to Win7. Perhaps this occurs with all dual boot computers. Well, and then you say the FREE CUBASE APP works. Maybe you should uninstall the FREE APP, have you thought about this? Perhaps Bonjour is confused, and yes, I only have the iC Pro app on my devices.