Scott
Jumping chains are common on AZQ,s kit should come with pullies and is cheap (from memory £70ish plus vat). Some-times pullies wont fit and you have to use the old ones.
The main reason i have found for the chain to jump is a misfire or if a clutch is changed and the flywheel not locked and the engine turns against the normal direction of rotation which realease,s the the tension from the tensioner, while torqueing the clutch cover bolts.
Kev.