i need help please

my clio 1.6 dynamic has started making a knocking noise at the back left hand side it is not frequent but i cant find the sorce of the problem has anyone any ideas

I know it sounds really stupid but my motto is try the simple things first, have you checked if you have anything in the boot that could be moving whilst you drive and settles now and again?

I only suggest as my friends "knocking" turned out to be this!!!

does this just happen in a straight line or more round corners ? check wheel nuts up tight and also jack up and see if any play in the wheel as it might be the wheel bearing