Watch List notes:

MS63 | The Undated Mule | Elizabeth II (1952-), Undated Twenty Pence, [2008], edge plain, 5.03g, 12h (S.G4A [4631A]), the first currency coin struck without a date for circulation in Britain since the reign of Charles II, a famous modern rarity, some depositories to obverse, otherwise much as struck, in NGC holder, graded MS63 (Cert. #6295118-010).

Estimate: £60 - £90