The Mamba as displayed here was a case of a good engine that never found a successful installation. It was selected for use by the Armstrong Whitworth Apollo airliner, the Avro Athena trainer, and the Breguet Vultur and Short Seamew naval attack aircraft. It was also considered for use by the Boulton Paul Balliol trainer. Apart from the Balliol (which ultimately retained the Rolls Royce Merlin), none of these aircraft attained production status.
However, when paired together to form the "Double Mamba", driving through a common gearbox, it found success in the Fairey Gannet, the British Navy's anti-submarine and radar early-warning aircraft from 1953 to 1978. In this arrangement, with the two engines driving contra-rotating propellors, the aircraft could cruise on single engine without loss of thrust balance.
The Gannet was also operated by the German and Australian navies. While there is no statement of the engine's origin, it can be presumed to have been obtained from the Australian navy.