Green’s Dictionary of Slang

ta-ra n.

[ta-ra phr.]

a goodbye, the act of saying goodbye.

[UK]‘P.B. Yuill’ Hazell and the Three-card Trick (1977) 130: Try to bung him a few quid for an accomodation and you could say ta ra to your teeth.
[UK]K. Sampson Awaydays 62: Birkenhead park, where the tunnel bus dropped us and where we’d said our ta-ras.