[CrankyCraig]

Thanks very much Dave, great advice. You're exactly right, I was completely unaware of the tags in the extended section. That explains why Kodi was doing so well matching them with, as I incorrectly thought, so little information. Though I've only spent a couple of mins trying, there doesn't seem an immediately obvious way to clear these Tags on mass. I'll keep looking.

You're also right to question why I do it this way instead of using Playlists. I think this methodology stems from a life before Kodi and Plex, when it was much harder to get devices such as laptops and MP3 players to interact with one another, and I was using playlists in other programs like Windows Media Player (shudder). Those were dark days, when copying files proved much more dependable than playlists, which would stop working because a single file had been deleted or moved. 

Since those days Plex/PleXBMC has been my primary music player, and it's worked well like this, though it has meant sacrificing playlists, and some lyrics and fanart. As of Monday I binned my ancient Kodi installations and started fresh, with a new skin, PlexKodiConnect and direct paths for music. I'd forgotten all about Kodi's playlists, which I'd been keen to try but never could. You've opened my eyes to a world of possibilities. Thanks again.

Kind regards, Craig.