Green’s Dictionary of Slang

churcher n.

[the Cockney version of society’s church-piece under church n.3 ]

a threepenny piece.

[UK]J.W. Horsley Memoirs of a ‘Sky Pilot’ 254: The plainly modern ‘monkey on a gridiron’ for cyclist, [...] and perhaps ‘churcher’ for a threepenny bit appealed to me as a cleric.