I've done quite a bit of work on this in the last few hours. I need to spray the red band around the fuselage and do the prop but that can wait until tomorrow.
The airbrush just wasn't playing ball with the pre-shading
IMG_2050 by
harrison-green, on Flickr
The green was built up using a few different shades of green. I had a little bit of over spray near the tail so I tried a trick which was in SAM this month which is to run a brush dipped in thinner along the demarcation line and it should help blend the two colours. I'm not sure if it's worked though.
IMG_2057 by
harrison-green, on Flickr