My window is pvc and opens out from a vertical hinge (a typical bedroom window in an estate house) The bottom hinge seems to be broken in that when i close the window there is a gap between the bottom of the window and the frame, and the window sits too far out so hits the frame at the handle side when closing. I can pull the hinge side of the window in towards the frame and then close it ok. Can I replace the bottom hinge or do I need a new window does anyone know? Thank you