Definition of "bona"

SANDY: Oh, get him! The vanity of the man. Well, p'raps not Nelson then. How about reproductions of great masterpieces?JULIAN: A bona idea. Now, let me see...

1966, Kenneth Horne, Bona Tattoos (Round the Horne), season 2, spoken by Julian and Sandy (Hugh Paddick and Kenneth Williams)

Will you take a varder at the cartz on the feely-omi in the naf strides: the one with the bona blue ogles polarying the omi-palone with a vogue on and a cod sheitel.

1997, James Gardiner, Who's a Pretty Boy Then?, page 137

Bona to vada you.

1997, Ian Lucas, “The Color of His Eyes: Polari and the Sisters of Perpetual Indulgence”, in Anna Livia, Kira Hall, editors, Queerly Phrased: Language, Gender, and Sexuality, page 90

Order lau your luppers on the strillers bona.

1967, Kenneth Horne, Bona Guest House (Round the Horne), season 3, spoken by Julian (Hugh Paddick)