As to who made it, hard to tell without having the gun to inspect properly and then some reference to historical records would probably be needed to get to teh bottom of it. Firms like AA Brown were making guns for others (like E.J Churchill and Alex Martin), Webley were doing the same, as was Edwinson Green. John Robertson was making (or stocking and finishing) a good number of guns for the London trade at one time.
Many of these guns were started with commonly available barrelled actions and locks supplied from the trade so operationally are often very similar; and difficult to trace to a particular line of production prior to retail.
