I am right stressed out with a problem on my focus 1.6 LX Saloon ( Auto )

When I drive over small pot - holes or uneven roads I get a rattling sound that sounds like metal been to ATS & Halfords Auto centre and both garages can not find the problem. All is as it should be under the car there is no play in anything and the brakes are not rattling around it's gets very loud sometimes and it make the car sound like a wreck.

What can I do or what can I try to solve this problem or does anybody know where I could go I am in Liverpool..

Thanks People