Thanks JimH
Tried various drivers in Options/Audio setup eventually got there with the Realtek ASIO driver but playing about in windows sounds setting (Win 11) it looks like on my laptop (ASUS Vivobook, Harmon Kardon sound card) Windows is not detecting and changing to the headphones in the MC34 app setting. Changing it manually does the trick. A bit weird but I can put up with it as a solution