It is a Cotterill Climax detector lock, although in truth very few of the locks have the detector, or anti-pressure mechanisms present.
Patented in around 1840, and made through until about 1910 or so.
Most are exactly as you picture, but some of the very best bank locks are superb. I should soon have some nice Cotterill locks and plan to post information on them.
Thanks for your post.