Further update and happy days....
Found the source of the rattle. probing around with a long screwdriver I managed to feel/source the rattle to the actuator arm and could noticeably feel it back up threw the screwdriver. So very carefully bent the actuator bracket away to tighten up the arm, and heypresto no rattle and better still is the turbo is now spooling sooner, with more of a punch and as I would expect. The car feels so much more responsive in the lower rev range.
Scott the noise was resonance on the actuator arm. Glad I didn't go to trouble of popping the turbo off.
Fallen back in love with it now...
