Watch List notes:

George III, mule penny, 1806, laur. bust r., date below, rev. laur. bust r. (P.1340; cf. S.3780/6620), in plastic holder, graded by NGC as About Uncirculated 58 Brown, extremely rare
£1500-2000
The 'reverse' is struck from an obverse die of the current 1805 Irish penny.