Does anyone know if there is any adjustment on uPVC door handle gearboxes? The type you have to pull up to lock all of the lugs in place on the door before you can turn the key? We have one that will open and close but I cannot lift the handle above horizontal and so cannot lock the door. I have removed it and taken some pics below. Is there an adjustment or does it need a new gearbox? - it isn't stiff, it simply wont go above horizontal