You guys crack me up. I said "hand detachable locks are one of the small refinements that separate nicer guns from ordinary guns". Your missing the "one of". All nicer guns don't have hand detachable locks just as all nicer guns don't have disc set strikers or chopper lump barrels just to name a few features.

For the record I did see a picture of one Purdey SxS that had H&H style detachable locks & was represented to be original & certainly looked that way to me. It did look sort of strange to me on a Purdey.