Watch List notes:

G William IV, pattern sovereign, 1830, plain edge, bare head r., rev. crowned shield of arms (S.3829B; W&R.260; Douglas-Morris 178), certified and graded by PCGS as Proof 64 Deep Cameo
A beautiful piece and as far as we know the first time this has been put up for auction. Only one other example has been graded this highly by NGC or PCGS. (£15000-20000)