Ah I immediately see my problem, as the audio indicator is on the actual main window and hidden by the settings window. It appears that my values are different (oddly) between OBS classic and OBS studio. Made it a little difficult to perfect it without moving the window. A silly oversight by myself, was used to seeing it on the same screen.
Example (Closed/Open)
Classic: 17/16
Studio: 17/13
All good, many thanks for the software, its awesome! :-)