Driveshaft or diff *clonk*

[falcott]

Geoffrey,

Lie under the car and work your way down the drive chain starting with the front of the propshaft back to the torque tube. 

Hold each part and move it up and down, looking for free movement, the source of the clunk will become apparent quite quickly.

If you find no movement, come back and I can suggest another potential source of the noise.

Thanks Ruaridh. I've developed a sore back from hunching over the front brake hubs (bad back from decades of very heavy lifting in my younger days) so once that's sorted itself out I'll get back to you all.