But I also do not believe that Holland and Holland.....made their original reputations by having the "primary" manufacturing done anywhere but in-house.
That's exactly what Holland & Holland did.
Ford and GM are not the same as Ferrari and Porsche, and history in the auto industry shows that as soon as major prestige marques start outsorcing too much the justification for the high price begins to erode.
Which has nothing to do with the British gun trade. Ignoring the established traditions of an industry you're not familiar with won't change them. In the past, much more outsourcing was done, and with a wider scope, than is the case today, and no, it didn't have that effect. Far more than just using highly trained outworkers today, in the past, a great many British guns were "bought in" from other gunmakers, usually in Birmingham - from proven barreled actions in the white to completely finished guns. That didn't mean that the retailing gunmaker didn't retain full control over quality. It was entirely up to him to set that standard, and reject the work that didn't meet it. If he let poor quality out the door, his reputation suffered, and it didn't take many turkeys to do fatal damage.
Birmingham's great gunmaking center is long gone now, but while the infrastructure of the British gun trade has changed, the bottom line today has not. You can still get all of the quality that you're able to pay for. It's much harder today to retain the very best workers on payroll - because the demand for their specialized skills means that they can make more self-employed. Does that mean that your gunmaker shouldn't use the very best stocker they've ever trained to stock your gun because the guy happens to be self-employed now?
Rolled engraving is not the same as hand engraving, even if the rolled engraving is absolutely perfect which the hand will never be.
This is a red herring. No British best is going to be sent out with rolled engraving. If Purdey sends your new gun out to Phil Coggan or Ken Hunt for engraving, does that mean you got gypped because it wasn't engraved "in house" by a guy you've never heard of?
The last new Purdeys I've seen were still finished to the high standard that Purdey is known for. Unless something has changed recently, they don't do colour hardening or blacking "in house". They send it out to the best in the world at that work, the same company that any other UK gunmaker can use if they so desire. I guess that makes them fake Purdeys.