Hey Sharpiee, I to an having a turbo control unit but on a Commander 3.0lt CRD. mine threw a P0234 Turbo over boost. My local mechanic tested it & said there is a fault in the actuator or boost control unit. I didn't ask him how he tested it, but I will next time I see him. As Spectre said, you can't buy them separate from the turbo & nearly impossible to get a second hand one. However if you contact Turbo Developments in the UK, they repair or do exchange units for around $300. They could also help you with your turbo as well. Also try
www.j-p-r.com. If one is available in Aus, they will know.
Good luck mate.