Watch List notes:

AU DETAILS | George IV (1820-30), silver Pattern Shilling, 1825, by William Wyon and J. B. Merlen, head left, . GEORGIVS IV DEI GRATIA ., rev. lion on crown, ornament of shamrock, rose and thistle below, BRITANNIARUM REX FID: DEF:, edge milled, weight 5.64g (ESC 1264; Bull 2147 R5). Toned with a vertical scratch on the neck, has been graded by NGC as PROOF AU DETAILS OBV SCRATCHED otherwise good extremely fine and very rare.

NGC Certification 6321659-008. (Incorrectly called a Sixpence by NGC).

This rare pattern is similar to the regular issue Shilling, but here the lion is smaller, the crown is narrower and deeper, and the legend is split in half over the lion.
Estimate: £3,000-4,000