After migration to new macmini M4, Premiere Pro no longer imports audio.

So first things first.  I have uninstalled and reinstalled the latest version of Premiere Pro. I have deleted the cache. I havedouble checked that all settings match the iMAc that runs Premiere perfectly. I have tried to import audio as mp3 and wav. When I double click the media in the source panel and click on the audio I am greeted with green. See pic:

If I try and drag the imported file into the sequence i get the no entry cursor. See pic:

When I drag an imported video (where the audio can be heard in quicktime - both iphone and dslr files) I get a video track but no audio track - even though V1 and A1 are toggled on. See pic:

Maybe I'm missing something really basic but I am utterly bewildered. Anyone have a solution that doesn't involve something I've already tried...updates, reinstalls, checking the video has audio in an different media player, correct toggling of V1 and A1 etc etc?

Any suggestion greatly appreciated.