When I lift up the handle to lock the back door a latch should extend out top and bottom into the door frame. Only the top latch is coming out, so door is not secured at the bottom. When you lock the door and go outside you can push the bottom of the door inwards. Not ideal!
I've unscrewed the strip that runs from top to bottom on the edge of the door and I can see there is a strip behind this which moves up and down when the handle is lifted up/pushed down. This strip goes into the back of a 'lock' at the top and the bottom of the door. At the top of the door it pushes out the latch, but at the bottom of the door although the strip moves up and down into the back of the lock it doesn't push out the latch.
These locks at the top and bottom of the door are fastened to the strip with what look like self tappers, but I can't loosen them to remove the lock!
Any help would be gratefully received. Female with a bit of an idea on how to take things apart but now stuck!
You do need to undo the screws holding the bottom throw mechanism in place, as you say they are probably self tappers. If you undo the screws holding the lower actuating strip also you should be able to slide the throw mechanism out without removing the lock.
DIY how to tutorial projects and guides - Did you know we have a DIY Projects section? Well, if no, then we certainly do! Within this area of our site have literally hundreds of how-to guides and tutorials that cover a huge range of home improvement tasks. Each page also comes with pictures and a video to make completing those jobs even easier!