Shaking this dog's bone a bit more:

Plunger: One who plunges, or spends money recklessly in bets, etc. The Marquis of Hastings was the first person so called by the turf. One night he played three games of draughts for £1,000 a game, and lost all three. He then cut a pack of cards for £500 a cut; and lost £5,000 in an hour and a half. He paid both debts at once before he left the room. -- E. Cobham Brewer 1810–1897. Dictionary of Phrase and Fable. 1898.

tsuwm, faldage, can someone with access to OED see if the etymology of this use of plunger perhaps gives the name of this marquis as Benzon?