Green’s Dictionary of Slang

chockers n.

[ety. unknown; ? rhy. sl.; chalk = walk; or ? chockerblockers = dockers; ? a type of shoe]

(costermonger) the feet, or boots.

[UK]X. Petulengro Romany Life 274: Chockers – Boots.
[UK](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) .