[Closed] Worn Chain or Bent Cage?

For some reason, I can no longer shift onto the granny ring. Even with no tension in the shifter cable and the limit screw wound right out, the mech (XTR m970) wont go low enough to push the chain onto the granny. I can't see anything fowling the mech, so think this is as low as it can physically go. The cage doesn't look bent, but its a bit hard to tell with the way it's shaped. I know the chain is fairly worn and was wondering if this alone is enough to stop it shifting?

Everything used to work fine till I had a long wet/muddy ride with a couple of crashes, so a crash could have bent it, or the ride could have killed the chain (it killed both brake pads, bottom bracket and headset!)

Anyone had anything similar or suggestions on what to try?