Logitec C920 Webcam - No Audio

Hi

I've been using my Logitec C920 Webcam on my 2018 Mac Mini quite happily for a year or so. This week most conferencing apps haven't been able to pick up the audio (zoom/google meet/teams etc) and as yet I can't find a fix.

In Sound settings the audio input monitor is showing a response when I click/clap etc..

But then any incoming audio isn't being routed to the meeting software. Here's a screenshot of the error as shown in Google Meet.

I've tried the previously reported fix of changing the audio sample rate frequency which did nothing. Here's screenshot of current settings there:

I've also tried installing the LogiTune software as there was an earlier bug reported there - but no fix here either. I've just run an update on BigSur from 10.5.6 (I think) to 10.7.9 - still the same.

I've run out of trouble shooting options - any advice?