malc
I think you may be thinking of a different window type.
This a window 720mm x 1250 mm in a bathroom.
The "hinges" are lever type top and bottom with a moveable lever about 30mm long on the top lever. This lever is approx. in middle of window. When I hold the top of the window in, it moves toward the inside of the window recess as it turns then stops abruptley. At this poin I can't see what is stopping it? I seem to remember on a previous similar window the top middle lever had something to do with it. I have tried to it in several positions this time without success.
Voyager
November 2008