Watch List notes:

William IV, proof sovereign, 1830, plain edge, second bust r., nose to second I in BRITANNIAR, rev. crowned shield of arms (S.3829B; M.15C), certified and graded by PCGS as Proof 64 Deep Cameo
*ex St. James's Auctions, auction 39, 2016.
The only example awarded Proof 64 Deep Cameo by PCGS.
Rarity R6.
(20000-25000 GBP)