Thanks John, I have attached some measurements of the existing lockYes.
Provide detailed measurements and photos of your existing device.
Hi John, the door handle in the picture is just to pull and push the door. It has no other use, it was the original handle from when it was just a latch.Your first photo includes door handles.
Your second diagram does not, but has a keyhole.
I deduce it is not a picture of the same thing.
Hi John. Yes the photo, I have issued is from a similar product and not the exact.It may well be a Union 2677 Mortice Latch, or the Zoo copy.
When you take the old one out, if it is painted gloss black, it may be a Legge.
I still think the diagram is a stock photo you have copied, and not your own actual lock.
Your old lock is more likely to measure in fractions of an inch rather than mm in round numbers.