there is a clip that locates it in place in the actual bit that goes into the door
do you have the sheidilng around the lock as wll welded onto the runner?
this makes thngs fairly difficult to get back togetehr again

and there needs to be a screw to hold in place at the bottom of the door towards the back, just obscured by thesticky foam stuff, philips screw with an M4/M6 thread i think