Green’s Dictionary of Slang

posh korona n.

also posh-korauna
[Rom. posh, half + korona, crown]

half-a-crown, 2s 6d (12½p).

[UK]F.W. Carew Autobiog. of a Gipsey 41: When they were felling timber Neptune used to tipper a posh-korauna to the vesh-dikkimengro.