The bright sky looking out the window made for pretty easy layering of the two images. Gives the children something to look at!
I increased the contrast and color saturation of the foreground image, then used a curves color adjustment on the castle image to closer match the original background color. Set castle layer to darken and masked where necessary to conceal detail that carried over into the foreground room.
Flipped the castle image and added the reflection in the tabletop.

forum discussion: http://forums.dpreview.com/forums/read.asp?forum=1006&message=27264322&changemode=1

original images by Jim Stirling:
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