amal valve sits on the top of the gearbox just under dizzy, with 3 pipes one from turbo and one going to actuator, it controls boost, should click when you turn on ignition.

Sounds like You really need to get it too a rolling road, you could be changing things forever and never get anywhere, could be something as daft as the gasket at the throttle body, but would be best to take it to someone decent to have it checked out, may work out cheaper in the end rather than just changing random parts.
Jay