George III, sovereign, 1820, obverse struck from a proof die, legend type B (ascending colon after BRITANNIAR, space between REX and F:D:), laur. head r., rev. St. George and the dragon (type S.3785C), scarce and unlisted in the Standard Catalogue, as struck
bt. Mark Rasmussen, 2016, with a printed copy of the original listing.
(4000-6000 GBP)