Knocking noise

[sbeatti]

I've had my c-class coupe for a few months now. In the last week I have noticed that when I reverse park I hear a single "knock" coming from somewhere around the front wheel on the drivers side. I ususally hear it just before the car straightens up as I am reversing back and to the right.
Anyone any ideas as to what this could be, and if I need to do anything about it. Fortunately car is still under warranty.
Susan-

 

[MSG2004]

Still under warranty - phone to take her in and fault find/wait and then book car in for a smae day repair.

Normally it is the passenger front side that knocks going over speed humps and uneven surface in roads - shock bush and link is changed to cure knock.