Watch List notes:

The Hardcastle Collection | PROOF 64 BROWN | George III (1760-1820), Proof Halfpenny, 1806, laureate and draped bust right, K • on neck, faint top pearl in brooch, rev. Britannia seated left, holding branch and trident, ship in left field, stays on masts, no line under [SOHO], rock touching hem of robe, edge obliquely grained, 29mm., thickness 2.4 mm, 9.46g, 12h, (Peck unlisted, cf. KH 34 and 41-43/34-35; S.3781), a seemingly unrecorded proof with a faint flaw before G running to 1 of date, otherwise much as struck, and very rare accordingly, in NGC holder, graded PF64 BN (Cert. #5878622-007).
The obverse clearly shows a faint top pearl on the brooch but also a wide space betwee the K and the dot
Estimate: £400 - £500