Not wanting to overtake Ants thread with this but with mention of the later locks and variations etc, thought I’d show it. Had this for years and always assumed it was a Bates. Key goes in a short distance in the vertical position, turns a quarter turn anti-clockwise, then pushes in against spring pressure to fully enter lock, turns back clockwise to fully unlock. Always assumed this feature (fitted as a nozzle on the cap) Deterred both picking and entry of black powder. Always seemed to encounter these safes being used in Post Offices, but they obviously date back long before the Grade 1s, Grade 1A’s and modern Tann PO issues.
They are a nice lock and certainly have many of the George Price features, but with a case size of nearly 4 × 5 inches and a weight to match they dwarf the Ne Plus Ultra. So was wondering what the link is with this one, whether it’s Bates or Gibbons’ progression of Price’s idea.

Apologies Ant- let me know if you want an old blank like the one I used Here for yours