33 Half Moon came out of South Africa and was a radio sensation in its day. "Assignments Unlimited" was the name of the PI firm in this
airwaves success. The Chief Investigator, Aubrey Mason, guaranteed successful completion of all cases...which was a tall order since most their cases were the uncommon.
The voice of Mason was Michael Todd, an extremely popular actor in South Africa. During its run in 1965-66, the show was written by Adrian Steed and then Douglas Laws.
The private investigation office was at 33 Half Moon Street. [archive.org]