grinding/crunching noise

hi all my 2007 grand scenic has developed a strange grinding/crunching noise coming from the front drivers side when going over the wider type of speed hump my local garage changed the mcpherson strutt joint as the bearing was shot to bits this though has not cured the problem and apart from the strutt joint they can not find any other mechanical fault which is good for my pocket but not my sanity as this noise is truelly annoying any help with this issue would be greatly appreciated