How can we box in part of a window to allow fitted wardrobes without bricking up and replacing the window?

If i were you,i would just have wardrobes fitted short of the wall a little and use that space for something else......maybe open shelving tapered in. Carl.

It's never going to be easy to make it look right from the inside or outside. If you've no other options it maybe possible to make it look better from the outside by putting a reflective film on the window glass. This will reflect light and hide the fact that it is boxed in on the inside. Then on the inside you could fit a scribe panel between the wardrobe and the window (hopefully the vertical strut) to box in and make it look solid and tied in. But like I said, it's very difficult to make it look right. Andy