Can I Change Track Attributes Without iTunes?
Well I found a way but it's not easy!


Locate the file in the Media Type > Voice Memos folder.
Double-click one of the audiobook tracks to play it in iTunes.
Right-click the play-bar at the top of iTunes and choose Get Info and you can change that track back to an Audiobook.





You could do this for every track but in my case I found that doing this revealed all of the Audiobook tracks under My Music even though they were still tagged as Voice Memos. So I could select all tracks from there and use Cmd + i to convert them all to Audiobooks in one hit.


Quite a long workaround but hopefully this will help someone else, I'm just glad my audiobooks are playable again :)