Thanks for the replies folks

Spent a bit more time on it today and made a bit of head way

The guys that said actuator are half right, what we found was that the actuator bracket on the t34 was bent slightly out of shape. This meant there was barely any preload on the actuator. Swapped with a better bracket off a spare turbo and it has improved a fair bit

Still doesn't feel quite right for the spec though. Going to pipe in the boost gauge tomorrow and bypass the amal valve and see what happens then