Watch List notes:

George IV, proof halfcrown, 1825, bare head left, rev. crowned helmet over shield of arms, plain edge (S.3809; ESC.2373), certified and graded by NGC as Proof-63 Cameo, a choice specimen with appealing golden bluish grey toning, rare
The only one graded as Proof-63 Cameo by NGC, none higher.

Estimate: 3000 - 3500 GBP