I got really excited when I saw the thumbnail Stewart cause it looked like an beautiful bluer sky background with clouds and I was wondering how the heck you pulled it off :)
Grass looks a bit too bright, the HA could be better and the OOF scum stuff, especially the bright spot above the bill lessens my excitement from the dreamy blue clouds and sky illusion in the small version :)
The removal of that spot has lifted this one for sure. I quite like the BG pond scum, kinda reminds me of a distant view of the earth I think desaturating the green grass just a little will put even more emphasis on the subject.
The grass is a little too mown for my taste, Stuart, and the water is not too great either. Nothing wrong with the foreground, it's just that the habitat looks strange.