Turns out I'm an idiot. Over an hour yesterday and today trying to solve this. I had my songs sorted by favourites. I favorited all my previous CDLC and a few other songs in the game. All the new stuff I put in the folder and cherub rock were in the game just not selected as a favourite. I bow my head in shame
For some reason my account no longer has cherub rock but my sons account does. It's on the same computer where we play. All the older cdlc is still playable on my account but anything new I add to the folder only adds to his song list and not my account that no longer shows cherub rock. Any suggestions?