Mr. Beesley sold his spring cocking patent to Mr. Purdey in 1880. He would have had to pay a users fee to Mr. Purdey to use his own action if he were to make a Purdey type gun.[I have seen only 1 Beesley marked gun with a Purdey type action.] He also patented a few other spring cockers like the Lancaster "wrist breaker". The Beesley's patent on the gun in question I believe refers to his ejector, otherwise known as the Southgate, or, if a Holland, the AB.[ two moving parts,not counting the spring, the hammer going overcenter]. I have seen a number of guns with the "fern fences" by makers other than Purdey or Beesley, some on backaction guns from Birmingham. I just noted that most, if not all, Beesley best guns had them. Although known as "the inventor to the trade" Mr Beesley made relatively few guns; I think his serial #s started at 1000.[ Don't have references here]. He was a perfectionist, and his creations rank among the finest.
All the best, Mal