Watch List notes:

British Coins, Isle of Man, James Stanley, 10th Earl of Derby, proof halfpenny, 1733, in silver, eagle and child above cap, rev. triskelis, I D 1/2 between legs (S.7409a; Pr.29a; M.50), certified and graded by PCGS as Proof 20
Estimate: 200-250 GBP