Originally Posted By: gunman
Just a very basic lock fitted to any number of low grade guns.


Gunman hit the nail on the head, as usual. Simple, low grade, back action trade lock probably manufactured in house by Tolley (1879 patent action) in Birmingham for sale to the trade. “Duck bill” style locks were seen as a cheap, out of fashion and not pleasing to the eye. Low grade does NOT mean low quality. The quality is still there...