How do I find out what's wrong with a uPVC window where the handle turns but it doesn't open?
It seems like one of the hidden latches along the edge isn't undoing because one side of the window moves out a couple of mm when you lean on it but the other side doesn't. It's a horizontal window with the handle at the bottom.
The bottom left moves a bit, the bottom right doesn't:

Is it worth taking the glazing out and / or removing the handle, and how do you do it?