Okay folks, I've now cleaned the EGR and solenoid it was pretty gummy, would push in with finger force but not spring back (astra 1.9cdti 150 btw).
I've also cleaned the turbo sensor (also very gummy) but the turbo still pulses beyond 2200 rpm and the turbo also seems to have got quieter in the last few days.
I'm suffering a notable loss of power, the car can get up to about 120mph but not anywhere nearly as easily as it used to.
Just to recap, I've recently had a new gearbox fitted, the car was parked up for the best part of 6 weeks in the shite winter weather without being run due to waiting for the GB to arrive. It worked for the first week with no notable acceleration issues then it started with the problem described above.
Next port of call is to check is any of hoses have been knocked during gearbox fit, does anyone have any diagrams/pics of the turbo and hoses as I've never got close to it before, also is it easy to get to??