Thanks for the comments fellers. Apart from being a crop it's just as shot. It's a very contrasty image, being taken in strong sunlight at just the wrong time of day really. The image doesn't respond well to levels alterations without losing the mood, so I've just left it as is. I thought about toning down the lighter shoulder on the left side.
I also tried doing a vignette effect to darken around the edges and emphasise the expression, but it doesn't work with the obviously strong lighting and looks manipulated.