Well BMW had the car in to change the bolts on the subframe as some of them were not where they are supposed to be (oops maybe i tightened them to much) and they said they had torqued them to 104Nm.
in the mornings when setting off when car was cold the clunking started again but almost went away when driving for a while.
I was not satisfied with this and was sure the bolts needed to be tighter.Mmmmmm
OK I decided that the problem had to be with the sway bar as the clunking was drop link clunking.
I found the sway bar was solid in the bushings and would not move up or down. Nailed it!
The sway bar could not move up or down with the shocks and was acting as a big torsion spring, I am surprised the drop links did not snap under the stress.
Sprayed WD40 on the bar in the bushes and the noise has disappeared completely even when cold. BMW do not sell bar separately so £200 for the privilege. No Poly bushes from Powerflex either?
So there you have it. Clunking may not be drop links check sway bar bushes first. Three dealers have thrown thousands of pounds of parts and labor and all it needed is a bit of lubrication.
Hope this helps a lot of people with this new and innovative car and the new problems we all have yet to encounter