Green’s Dictionary of Slang

(costermonger) the feet, or boots.

1935		X. Petulengro Romany Life 274: Chockers – Boots.
1979		(con. 1920s) J. White ‘Campbell Bunk’ in History Workshop 26: A rich veing of slang which harked back to an older London street culture [...] Words which were not current in ordinary working-class speech [...] chockers (boots) .