E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Plates or Plates of Meat.
Slang for feet. One of the chief sources of slang is rhyme. Thus meat rhymes with feet, and warming my plates is slang for warming my feet. Similarly, Rory OMore is slang for door, and there came a knock at the Rory OMore means there was a knock at the door. A prescott is slang for waistcoat. (See CHIVY.)