Just tried this all again and experimenting with a new empty project etc… I got it to work. I took your comment “All settings you make in the Audio Connections > Control Room is global” to mean that any of those settings ought to be retained upon closing of cubase, rather than finding a specific dialog for them. Ultimately that was very helpful to me.
I haven’t got to the root of the what was happening but perhaps something to do with the F4 Audio Connections > Output setup in a particular project was overriding the control room setup.
But I have now managed to open existing project and new project with existing template too and find the audio in the order that I wish.
Thanks very much for your help - much appreciated.
NB And in answer to your question “what am I trying to achieve?” The only reason I’m doing this is so I have some control over the metronome volume whilst playing/ recording in the project. It feels like using a sledgehammer to crack a walnut but it seems to be the only way of doing it in the latter cubase versions.