well lads,
After doing all the above tests for various areas of play, and after talking to a much more Land Rover clued in friend of mine, we decided it had to be the diff in the T/box that was causing all the hassle.
So stripped out the old one and replaced with a disco t/box which had been rebuilt.
Clunking is still there!! its definitely not the aframe, drive flanges, t/box, props or uj's and all bushings and suspension parts are less than a year old.
any suggestions? as im running out of ideas!!