I do have my library and show entry configured this way, but maybe something is stuck somewhere in the database. I’ll do the old plex dance now and report back shortly.
EDIT: Yep, the full plex dance seems to have done the trick and it’s now matching correctly without my intervention. Some data is missing (synopsis, original availablity date, studio, etc) but the really important stuff is there. I did have to explicitly remove any reference to the TVDB id in the directory name and .plexmatch file though or it would still match to Choujuu Sentai Liveman. So the mismatch between TMDB and TVDB is still making things a little janky I guess, but the main thing is it’s working. Now to re-add all my watched data 
Appreciate the help @BigWheel, cheers mate. 
