OK - got this working finally. There was no audio device installed. I installed somerthing else that I was hoping would test the sound - I chose “DXX-Rebirth: Descent” and while it didn’t start successfully the act of installing it seemed to fix the sound issue. The skin sounds in kodi were noticable again at launch the audio device was now listed rather than showing “error - no device found”. Now playback is working fine!
Thanks for the lead @ QBurris64!