Window handles come in a variety of types, but the two most common are:
‘Cockspur’. Not so commonly used in modern windows. Are screwed to the face of the window, and secure the window with a ‘nose’ that engages onto a pad on the frame. Generally key lockable, but older variants may use a fiddly ‘allen’ key and screw to lock. Some may not have a lock.
‘Espagnolette’. These screw through the face of the window sash to secure a square spindle into a locking mechanism inside the window. Operation causes multiple locking points to engage into concealed keeps. Generally key lockable*.
We can replace both the above types in various sizes. Mostly white from stock but individual requirements can be discussed and quoted.
* Building Regulations require certain windows to be available for emergency escape or ‘egress’. These must not be lockable. New window installations will have a green button in the handle to indicate this.