FYI

Right, my 1.8 zetec started doing the same thing also. Took it for an MOT yesterday and they had to replace a worn droplink bar (from the anti roll bar down) NSF.
The car came back from the garage and is now quiet again. With this in mind I removed the NSF wheel on the 170 to find my droplink bar rubbers had also perished, problem sorted. I have purchased and fitted a new pair and the noise has gone