thanks for your help guys - One question - where exactly is this lever on the turbo.......when I did the innotec clean I could not find it. Is it best to access underneath or from the top?
 
The thing the actuator's connected to, that's the lever bit, not sure on your car but on my mates Mk4 golt gt tdi it was quite easy to get to from the top.:)
 
to disconect the actuator, do you have to drain oil or anything like that, or can you simply disconnect and reconnect.

how do i check pipes for leaks?
 
No just disconnect it, no need to worry about oil or anything, it's just a diaphram with a spring that works off vacuum to move the lever on the turbo to work the vanes and it's totally external.:)
 
so just disconnect and give a shake?

Could the MAF have anything to do with this?

(bear in mind that since I have done these in-tank treatments the car is running a lot better)