Argo44, not sure if any of this is helpful, but some time ago I had about a dozen original hand written contracts between Westley Richards and various gunmakers wishing to use their various patents, including Deeley controlled patents. Each of these contracts specified the payment for each patent use and that the other gunmakers were to bring by their guns using the patents to Westley Richards for inspection and numbering of the uses. Exceptions to this process were later granted to Scott who would not bring the products by for inspection and Harrington Richardson in the U.S. , who had sole U.S. license for the Anson Deeley patent. H and R would use the serial number as the patent use number.
I have a Richard Jeffery pinfire with a Dougall Lockfast action with the Dougall Lockfast marks on the underside. Action is stamped J Wilkes in a mostly hidden area meaning that he was probably the actioner.