OK this was because one of the packages uses bluetooth and the privacy entry was not in the info plist.

Hi, Thanks for reply. what I meant here was I drag ''n' dropped app into Privacy & Security - Full Disk Access section. On my dev box this seems to allow the app to quicklook files on the file system (tried a lot of home sub folders including Dropbox, downloads, documents etc) - except for iCloud Drive. I can also see the extension in the Privacy & Security - Extension - Added extensions section in settings and the quick look preview is enabled there. I was able to get Xcode cloud going and created a test flight build. Upon downloading this to another Mac I can open fit files in the app to view but not use the QuickLook feature. I added app to the Full Disk access section but it is not showing under Added extensions. Thanks Ants