1785 EL Dublin to London with superb IRELAND

1785 Entire Letter from Dublin to London with a superb strike of the small IRELAND 44 x 6mm in brownish black (F/K 60), manuscript "6" in black, reverse with a very fine 22mm Dublin "Bishop" AP / 20 and a very fine 19mm London "Bishop" 25 / AP. This small IRELAND is rarely found in black on letters to London; however, the ink used for the straight-line matches the London Bishop perfectly, thus proving where the IRELAND was applied. 
An important reference piece proving the contention in F/K that this mark was not applied in Dublin.