Help needed with creaking 57plate Mini Cooper Auto

I wonder if anyone out there has any idea what is causing my 57 plate Mini Cooper Automatic to creak like an old rusty gate! The car has been to three garages and not one can find the problem,  they can hear it but don't know whats causing it. The noise is coming from the passenger side, I can't identify wether it's at the front or rear. On a nice smooth road you can't hear it, but on our lumpy Cornish roads its there most of the time and gets worse when the wheel is turned to the right. Can anyone offer any advice, apparently the garages have checked everything and found nothing but it is now getting louder and it's very annoying. Help.