Most window winders are held in place by a horseshoe shaped spring clip,get a piece of stiff wire and make a small hook in the end (a right angle will do)point the winder handle downwards push the plastic ring toward the door and you will see the clip,hook it and pull it upwards,the handle will come off,to replace it put the clip on the handle first,put the handle on in the position you want it and bash it with your fist,it will pop back on again.Re list if it is a different fitting.
Rich, January 2010