Thank you Mark for your feedback.
Yes, I want to keep my Apple Music files in case I choose to stop paying for access to more Apple downloads, and also I want to be able to play them in the car, which will play FLAC files but not m4a files.
I still have some cover art because I did manually download a few jpgs which now sit alongside the FLACS in the album folder. I also have yet to convert a few m4a files and the covert is embedded which is standard for Apple music downloads, but I will be converting everything to FLAC soon.
I'll do some digging and see if it's possible to extract the coverart from m4a files on a mac like you can under Windows.
So what you're saying is that it's not possible to get the B2 to search for relevant artwork for its internal FLAC files, like it does when you burn a CD. That's a pity.
Peter