DanzaLFC wrote it used to let me play them before the update on the challenges, it takes me to the challenge but i cant chose my diffuculty and play there is nowhere to chose to play.

There was a while when it did this for me. But now all i did was went to dashboard after loading it up once, then eject the disc and put it back in and restart the game.
Then when you're going through the menus it should say press back to access challenges,
Sorted.