Hi and thanks for your comment! Its definitely a standard ecu as ive had it out to try to read some pin-outs. Cars in an absolute sorry state at the moment. I've widened the restrictor pill to a 1mm hole so it boosts less. Furthermore, I have taken the throttle body out and gave it a real good clean up - the idle control valve and channels were caked in crap. I have had an intermittent engine warning light (code 22 knock sensor) so i cleaned it up and torqued to specification and its now failed so waiting for a new one. This is where is gets a lot more crazy.
After reassembling the throttle body, and i only touched the throttle body, I now have code 21 (engine coolant temperature sensor) and code 45 (pressure sensor).
What the hell is going on!!??!?!?! Any ideas?? I originally gave a slight adjustment to the wastegate actuator but now returned it to normal.
Am unable to drive car until knock sensor arrives so not sure if this has put the pressure sensor correct.
Sorry about the rant, loads going wrong!!!

 

Did you try building the boost up slowly, by opening the throttle slowly?
did it still over boost?

The throttle body would not cause the issues you have been experiencing.
Does the car have a standard exhaust.
The boost is being pulled back by the ecu, because its rising to high.
If the ecu is standard, you can check this by looking at the model code on the case 800 or 801.
The boost solenoid or associated pipe work can also cause similar problems, you can clean these out with brake cleaner.
Clean the solenoid by removing pipes, connect the diagnostic connectors under the dash board, switch on ignition but dont start the engine, the solenoid will be pulsing, spray in the top hole and the crap should come out the bottom.
The other problems check all you connectors to the various engine sensors for broken wires or dirty connections.
I know these are more questions but it will help with the diagnosics.