Been doing some more digging into this turbo trouble I'm having. It turns out all turbo actuators need recalibrating apart from the Garrett Hella type. The w211 e320 and 270 are the Hella type. So this rules out the failure of the turbo.
228,000 miles on the original turbo isn't bad i suppose .
Just got to wait now for the Indy to strip down the turbo and parts that run off it, to see what else is buggered. Hopefully nothing. As this car has out priced itself with repairs now. Actually rather gutted as was driving so well. Great all-round the w/s211. To be expected with a car of age and mileage I suppose