Green’s Dictionary of Slang

Mrs Chant n.

[rhy. sl.; see next]

an aunt.

[UK]‘P.P.’ Rhy. Sl. 5: Aunt – Mrs. Chant.
[UK]J. Franklyn Dict. of Rhy. Sl.
[UK]J. Jones Rhy. Cockney Sl.
[UK]R. Puxley Cockney Rabbit.