The American market can be very 'trendy' regarding firearms. A Greener shotgun will attract a flurry of bidding at auction, whereas a Leeson or Turner may pass virtually unnoticed but for a very few cognoscenti.

Nevertheless, the volume rifle-makers in the UK were Westley Richards, Jeffery, Wilkes, and a few others, who made primarily high-quality boxlocks which form the bulk of the DR market. I suspect most Holland rifles offered for sale are sidelocks, which place them in a more select buyer group, not nearly as prolific as the former.

This may explain in part the disparity between WR and H&H, Checkman. I don't think geographic location of the US agencies would have that great an influence.

Anyway, not Gospel, just my thoughts.....