Actuator is definetely 1bar, its a genuine HKS GTRS kit for an RB25. Lots of people use this turbo with no problems so i seriously doubt that the rear housing is too small because im pretty sure garret and HKS would have found this out, afterall, HKS get the exhaust housing built to their specification.
Secondly, the actuator came mounted on the turbo when it was brand new and i have never removed it, other then taking the circlip of the end of the rod. The flap opens freely and doesn't hit on anything and the actuator is in perfect working condition, it opens over 90 degrees when the flap is disconnected, if exhaust gas cant flow properly through that then i dont know what can. I am nearly 100% sure it is not an issue with the actuator, nor is it an issue for the dump pipe as i have 2 completely different dump pipes and both do the exact thing.
The car will be tuned in January and hopefully it is due to the timing being so retarded that unburnt fuel is going straight through the exhaust manifold and igniting creating a sudden rush of exhaust gas, which in turn is spinning the exhaust turbine and creating boost that cannot be controlled by the wastegate. (Atleast that is my understanding of how timing is affecting this as this is roughly how i have been explained it)
So yeah unless someone has a better theory other then saying the actuator is f****d id like to hear their input.