SB - probably fair to blame USA for beaver tails (after all, the beaver being a USA rodent, Europe had no model) and vent ribs. But, you all are going to have to stand up to single triggers. Shoot, I doubt if theyada even been thunk up here until yourallz gunmakers figgered 'em out in the 1890's. And, you all were putting pistol grips on shotguns long before the first rich American showed up for a proper gun.

kd - why did the Purdey not pass muster? $15K should get you a basic working model. It will likely need some blacking, maybe so back on-face, maybe a touch-up to the lever work, a spring or two, etc. But, basically a first-run working gun. It won't get you one with a lot of original finish.