Keying out sky issue

Andy001z LordEarthPosts: 3,633 Ambassador

Hi I am trying to create an image using a photo I took at the weekend. I wanted to replace the sky. So I used the Hue and RGB key and got it to work OK, however as you can see in my screen grab the existing reflections on the castle inner walls have been keyed an the sky is also showing the colour of the sky.

Ideas? I think it has something to do with boosting the contrast or such and then keying?