Oh dear,
Warning to others, if you have a new lens that is stiff or clicks take it back straight away, particularly these plastic ones. Mine, a Nikon 55 - 200 dx zoom, did just that and is now busted, images come out a bit like a lens baby soft around the edges. Know returned to Jessops for repair, have to wait and see what occurs, guy thought I had dropped it, which was not the case.

Regards

David