Thanks for that Dave.
Update so far..
Have found that the PCM is not driving the TACM power relay. Fitted a temporary link in place of the relay, the Throttle actuator powered up and the vehicle could be driven.
So now its PCM out again (glad I didn't put everything back straight away), check I haven't bent any pins on the PCM (I hate connectors with big bolts in the middle, no feel to them) and check wiring continuity, going to be a bummer if the PCM is faulty, another programming charge.
Shaun