Green’s Dictionary of Slang

beong n.

also beonck, beone, beyonek, beyong, bianc
[Polari bianco, white; the shilling is a ‘silver’ coin]

one shilling (5p) .

[UK]Hotten Dict. of Modern Sl. etc.
[UK]Hotten Sl. Dict.
[UK]Sl. Dict.
[UK]Newcastle Courant 2 Dec. 6/6: ‘How much is it?’ ‘Tray beong say saltee’.
[Aus]Morn. Bulletin (Rockhampton, Qld) 18 July 2/6: For a shilling there are many names but nearly all slang. [...] ‘Breaky-leg,’ ‘brongs [sic],’ ‘bobs,’ ‘bordes,’ ‘drawers,’ ‘gens’, ‘hogs,’ levys,’ ‘pegs,’ ‘stags,’ ‘Shigs,’ ‘twelvers’ and ‘teviss’s’ .
[UK]P.H. Emerson Signor Lippo 47: Alright, give me due beonck quatro soldi per run and I’ll bring you the duckets.
[UK]J. Ware Passing Eng. of the Victorian Era.
[UK]P. Baker Fabulosa 289/1: bianc, beyonek, beone, beyong a shilling.