I had done both the Plex Dance, along with lots of refreshing, and 10cc uniformly refused to budge.
So, as I had only set this back up about 3 weeks ago, I uninstalled Plex and deleted all Plex directories on the Nas. I renamed my music library and created a new one with just 10cc in it, reinstalled Plex and set up the library with defaults (except ticking the use of my meta if present). Then did a scan, and… it’s worked…
Good grief, or more precise ‘thank GODley’.
So, no idea. I still have to retag all music to overwrite the release years (thats going to be rather a chore - anything quicker than MP3Tag?), and rescan (going artist by artist this time 
Still, I would adore the option to use the ‘original release’ year when present.
WOOT!
