@will_ainsworth
Can I ask why you used green? Its caused a great deal of green light to be reflected back onto his skin, which you've then had to correct. Shooting on a grey background prevents this totally. There's not really a need to shoot on a green screen for still photography. Green was chosen for TV work because green is complementary of human skin tones, so that's fair enough, but your green background here is way too bright, and you're actually getting green rim lighting around your model. There's no reason a background has to be green for this kind of work though. What you're doing is NOT Chroma Keying or CSO in video. You're MANUALLY masking your model off, so all you need is a clean edge. A grey background would have saved you a great deal of work.
A great deal of your layer mask work could have been automated with refine edge. With all these clean edges, and no long hair, refine edge would have got to to an almost perfect mask in seconds, and your manual mask refinement would have been much less.
Finished result works well though, and the lighting on the model is nice... sits well with the chosen scene.