Watch List notes:

(g) George III (1760-1820), Sovereign, 1820, 'Open 2', laureate head right, rev. St. George and Dragon, edge milled, 5h (Murdoch III, 100[b]; King - [cf. 186]; Marsh 4; MCE 466; Spink 3785C), a delightfully 'honest' example with ochre toning over original lustrous surfaces, a pleasingly good very fine / lustrous near extremely fine, in NGC holder, graded AU55 (Cert. #5879414-001).
In the cataloguer's opinion a charming example worthy of a higher third-party grade
Estimate: £800 - £1,000