Wow - cool guns. Thank you for sharing.
Here's another version of this design by Lancaster:
https://www.proxibid.com/asp/LotDetail.asp?lid=64732906From the listing for that gun:
"According to Geoffrey & Susan Boothroyd in their book “The British Over-And-Under Shotgun” (Chapter 16), H.A.A. Thorn, the then owner of Charles Lancaster, took out a patent (No. 12,057 of May 14, 1910) for "providing double-barrelled guns, of the kind having superposed barrels, with ejector mechanism". Expanding on the fact that the patent is for ejectors only, a letter published in "The Field" magazine on June 30, 1910 is mentioned that confirms the guns were purchased ‘in the white’ from Germany and were finished and fitted with ejectors by Lancaster in London."
I've seen similar phallic-style locks on other Lancasters. They were all SxSs, and I don't believe the locks had a quick- or easy-detachable feature.
BTW: Here's the full GI listing for the sidelock shown above:
https://www.gunsinternational.com/g...2-1-2-quot-game-gun.cfm?gun_id=101550378OWD