Another old rumor..."all the English makers could build best guns".
Hj - I make an important distinction between what you say above and what I said. There is considerable difference between building a best gun with all inhouse work and getting a best gun out by buying any best work needed from outworkers. Very few shops had the volume of demand for best work to keep all needed specialists inhouse to totally do a best gun. However, many shops could do some/most of the work and hire out some few jobs. Now, as I said, all shops and dealers could hire a complete gun made to best work standards. The catch in finding customers was that small dealers couldn't get a best gun out enough cheaper than a bigger name shop that cost conscious customers would come their way.
OK, Purdey's, et al, got a fair premium for their name. W. J. Jeffery sold his best gun for about 20% less. However, the local iron monger (hardware store) could buy guns, but couldn't sell a best gun for enough less than, say Jeffery, to attract customers who would most certainly recognize the Jeffery name and that name's value.
Trying to associate a given original quality grade with a maker's name will lead you astray. Brand name and original quality grade are seperate criteria.