The critical requirement for me when I was looking to replace my port side mortice lock was to find one without protrusions on either side. Plenty of solutions exist if you can have a handle on one or both sides, but to have no protrusions is often critical for those of us with narrow side decks and where the door must slide fully open, so an interior handle would reduce the opening width by an unacceptable amount.
I bought two at the time, as I predict the failure of the starboard side. I am not close to my boat just now, so I can't help you with the source. If you are still without a solution when I get to my boat, hopefully before the end of April, I will let you know what I can find.