Hello Adam, I'd agree with Neil. Remove cambelt & turn dephaser unit back & forward until it locks in the set position then check timing. Another thing these engines suffer with is the pencil type coils. Often these don't throw a fault code & the best way I've found to diagnose is a bit crude. I disconnect each coil in turn on idle, usually 1 or 2 will slow the engine speed, the others will cut it. I still haven't worked out why (as they are def. all firing & I can't see how they can fire at the wrong time?)