William IV, 1830-1837. AR Crown 1831. Engraver William Wyon.

GULIELMUS IIII D G BRITANNIAR REX F D, bare head right. WW (faint) on neck truncation.
ANNO 1831 beneath crowned shield of arms within intricate mantle surrounded by a chain and St. George below.

Seaby 3833. 
Rare. Only 100 struck. 

With permission of Fritz Rudolf Künker GmbH auction 293, Lot 1987, June 2017