Watch List notes:

(x) NGC XF40 | George III (1760-1820), Emergency Issues (1797-1799), Oval-Countermark Dollar (8-Reales), 1780-PR, Potosi (Bolivia), laureate and draped bust of Charles III right, oval countermark of George III in centre, rev. crowned square-topped shield dividing pillars, security edge, 11h (Bull 1857; ESC 131; Spink 3766), patchy tone, otherwise host coin very fine, countermark similarly so, rare, in NGC holder, graded XF40 (Cert. #3893062-004).
https://www.ngccoin.com/certlookup/3893062-004/40/
Estimate: £400 - £600