I assume you have the same page up as I do! Type your question into the Search part and you will find some answers.One of the first ones sums it up,the principal is usually the same.If you put the handle in the open position and push on the top of the window and it moves (on the lock edge)and push the bottom and it is firm,the shoot bolt has probably snapped near the handle and is stuck in the hole.I did our front days ago it is doable.You have to remove the glass (youtube might show you how)then go outside with a block of wood and a tyre lever under the opening side of the window,get someone inside pushing outwards on the top open corner of the window while you lever the bottom corner up,the frame will distort upwards and outwards and the shoot bolt should pop out of the hole,be FIRM but don't "rive" at it,lift and push a bit at a time keeping the pressure on steadily,you are knocking the frame out of square but it will spring back.Once open it's up to you,(stick something in the bottom plate to stop the rod falling in again).Good luck,Faint heart and all that.
Rich t
June 2014