Middlesex 503, Skidmore's (Dalton & Hamer, page 151)

Denomination: halfpenny, scarcity: Excessively rare
503.  O: Two men at a forge. MANUFACTORY . & . IRON-FOUNDRY . CLERKENWELL *
         Ex.: 1795. Same for Nos. 494-509, as rev. of No. 480.
      R: A cypher W G M, &c.
      E: Milled.

Nos. 480a-519, are with few exceptions exceedingly rare.

Keywords

manufactory,iron-foundry,clerkenwell,1795,wgm,halfpenny,1791