thumping at front end

Hi all
I have a 2010 2.0 chevrolet cruze lt vcdi on a diesel
i have only owned this for 4 weeks 3 of those weeks it has been in the garage for a new vapouratour due to leaking on the a/c which has been fixed and also to try and find knocking/thumping sound on the front end passenger side which the garage cant diagnose
the only way i can expain is when driving slowly you can hear a thumping rumbling sound more on uneven roads but when on a motorway traveling faster no sound
i have had the drop links changed but still get this noise anyone have any ideas
thanks in advance