I have one of those. Check out the small differences between the guns. The floor plate is shaped differently and is engraved with "Patent Block Safety" instead of your "Patent Safety". I don't have photo of the fore end, but my # 2 is located below the circle of the tip.
Toby Barclay, Heritage Guns UK, restored mine. I think he knows who has the Lancaster records and may chime in later.
Mine was made 1894, SN 07408 #2 of a pair. No idea where 1 is.




Joe