I'm posting this as question & answer because Google was no help at all for what turned out to be such a simple 'fix'.
Connecting the camera to the computer showed it as being seen by the OS, but no amount of pushing or poking seemed to make Camera Control Pro 2 be able to detect it. The app would simply show the error "No camera was detected" & hang there. The only way out was to force quit.
This symptom survived reboots & also updating the app [in all I tried 3 different versions].
How do you make the Camera Control Pro application recognise your camera?