At the top there's no socket and the pin's flush with the top of the hinge. Photo of the bottom below. Doesn't look like a hex or torx socket. As I said in my original post, I can turn that with a large flat headed screw driver but that doesn't make it move in or out or turn the pin.
I need to get a window off.
See photos below. The first two are the upper hinge and the second two the lower.
These are in Portugal made by GU.
I think the way it works is to get the pin out the top hinge, then the window will tilt in and I can lift it off the bottom hinge (having first...