Victorian mortice lock with a step - can get?

[JohnnyF]

Hi hoping someone can help. I have a pair of old porch doors that open in the middle.

The lock on it is like a mortice lock but it has a step in it (I'm not sure how to describe it!) where the doors join and overlap in the middle.
______
_I I
I______I This is if you were to look at the lock from top down.

Do you know what these locks are called? And where I can either get an old one or a reproduction one?

Thanks

 

[big-all]

do a google for"rebated mortice locks"

 

[JohnnyF]

cheers will do

i tried hinged, step etc but never though of rebated!

Ta