Division of labour - I'm sitting here laughing. I have to admire how your mind works to describe the locks as such. Thank you for explaining the difference because I sat here for five minutes or so looking at the photo wondering the same thing until I scrolled down and saw your post. And thank you Daryl for posting such interesting locks. I'm a died in the wool American SxS shooter but just love to see all the wonderful British guns and their interesting locks. I'd like to see a book published with all the different locks invented, and explained how they work. Just drawing would suffice, wouldn't need the expense of photos.