Green’s Dictionary of Slang

Romford lion n.

also Rumford lion
[joc. ref. to Romford, Essex, then a market town]

a calf.

[UK]B.E. Dict. Canting Crew n.p.: Rumford-Lyon, a calf.
[UK]New Canting Dict. [as cit. c.1698].
[UK]Bailey Universal Etym. Eng. Dict. [as cit. c.1698].
[UK]Grose Classical Dict. of the Vulgar Tongue n.p.: Rumford lion, a calf.
[UK]Lex. Balatronicum.
[UK]Egan Grose’s Classical Dict. of the Vulgar Tongue.