300846. The Woodward & Emme patent is just avoidance of the Purdey patent by using lugs on the front lump that engage with a very Purdey-like bolt! It is very similar to the Hodges patent no. 251 of 1871 that Grant used a lot in his hammerguns.
I am beginning to wonder if it is a unique action, built as an experiment and then turned into cash. I believe it happened quite a lot in those early days. However very few turn up as they usually didn't last!