Chris Batha's records start around late 1898 at around 13,000. Chris found the records for 13549. It was made Sept 1, 1899.
Chris stated that is was about the earliest records he has.
I used to have a Boswell SLE 12290. Chris couldn't date that gun.
I have a damascus 10 hammer gun SN 7016. It has patent dates from 1877. The proof marks are pre-1887. English patents are protected for 14 years. My 10 could have been made between 1877 and 1891, the proof marks further restrict the range to pre-1887. I just tell folks, the 1880s.
My 10 ga does have the Edmonton address. I have a Boswell trade label that is correct for my gun. It is not in the best shape.
It says: C. Boswell, Gun and Pistol Maker, Upper Edmonton, near London. And "old guns taken in exchange"
Joe in Charlotte