Great Britain 1820 Shilling with IS Counterstamp markn Posted in Great Britain Coins IS (or SI) Counterstamp on British 1820 Shilling Great Britain 1820 shilling with a large IS (or IS) counterstamp. Coin InformationReference Number:X4308/14Country:Great BritainDenomination:1sYear:1820Mint:Royal Mint LondonGrade:Good ‹ Great Britain 1797 Penny W. FENTON FULFORD Counterstamp Souvenir from an ANZAC Tin Badge ›