Think I've gone about as far as I want to with this. Thank you all for your help once again.
Any more input is appreciated:
@Segujo: Nice work, can't really see much to critique.
@Claude Crow: For me the image is too wide, but that drastic vertical line makes it almost look like two pictures. The pic is also a bit small for me to see much detail, so I can't really make too many suggestions.
@Smolin: Looking good, is coming along quickly!
@Rageful: Are you using a reference photo, because a few bits look a little 'off' to me - not least her foot and the arch of her back where it meets her butt. I like the concept though.
@Midscrawl: I tried to paint a city a little like that for a test background but you've made a far better job of it than I did. The only bit that stands out as needing a little attention is blending the elements together. It looks on some bits - such as the front character - like it's been collaged.
@Hansnomad: Coming together, the perspective on that back arm looks fine.