In the early 1950s, he moved to London, by way of New Zealand and the Pitcairn Islands, during which time he worked briefly for Ngaio Marsh's theatre company.

From initially earning a living by playing the piano in bars and clubs (he was briefly Noël Coward's rehearsal pianist), he developed an interest in design, establishing the fledgling Marble & Lemon decorative arts business in Cheval Place, Knightsbridge.

Bannenberg created the setting for the 3rd International Art Treasures exhibitions at the Victoria & Albert Museum in 1962—the design of which was described by The Times on 2 March 1962 as "well adapted to facilitate appreciation by the planning of its series of compartments".

[3] His profile continued to rise and, in 1965, he was selected by Cunard as one of the interior designers for their new liner—known initially as Q4, but later to be the Queen Elizabeth 2—under construction at the John Brown Shipyard in Glasgow.

[4] His clients included Larry Ellison, Malcolm Forbes, Alan Bond, Bennett S. LeBow, Adnan Khashoggi, and Robert Maxwell.