Hard to tell where the leak is from this picture, which you have inverted. At worst it looks like oil has weeped out from the cam cover over the top of the cylinder head. Interestingly, unless I am mistaken, your rear lambda sensor or plug lead (whichever one it is) appears to be mis-routed, it should pass behind the rear subframe and into the RH electical box. Then again, as I said its not easy when the image is orientated this way.