Nice painting - the natural light photos show that the green-grey colours are actually quite close to each other.
@ Andym:
If you like the camo colours on Space Marines, and have a soft spot for the mk6 "beakie" or "womble" armour, you might find the Raptors Chapter to your liking. They are a Raven Guard successor who specialise in stealthy fighting and have a green drab/olive as their Chapter colour
