VEVOR Dog Door for Sliding Glass Door, 75 7/8"-80 11/16" Adjustable Height Doggy Door for Sliding Doors, Aluminum Frame Tempered Glass Pet Door with Hinge Structure Flap and Lock for Large-Sized Dogs

I have a security sliding door on the outside , so if I had the dog door I would open it up so the dog can go in and out but when I want the security door closed and locked how do I close the door and lock it with this dog door on as it covers the lock?

My sliding door is 2100mm, will this fit as all I can see is it goes up to 2040mm

Does this lock to the rest of the house to stop people coming in? It doesn’t explicitly say