Green’s Dictionary of Slang

Auntie Ella n.

also Cousin Ella
[rhy. sl.]

an umbrella.

[UK]J. Franklyn Dict. of Rhy. Sl. (1981).
[UK]J. Jones Rhy. Cockney Sl.
[UK]R. Puxley Fresh Rabbit.
[UK]B. Kirkpatrick Wicked Cockney Rhy. Sl.