Singer fell into the arms of the Rootes Group in 1956 and their Hunter model was quickly despatched to be replaced by a Singer-badged version of the new Hillman Minx (Audax). Rootes retained the Singer 1497cc engine for the first Gazelle, but this was replaced with the same Hillman Minx 1494cc unit from the 1958 Series IIA Gazelle. The Series II in the previous year had kept the Singer engine but given the given the Gazelle curving side flashes and side grilles incorporating indicators, and an estate car model was added to the range. The Series IIA was quickly followed by the Series III in September 1958 which was given a less bold side flash and had the 'Gazelle' badge repositioned from the door to within the point of the flash. The Series IIIA was introduced in September 1959 with rolled over rear wings and triple rear lamps distinguishing the Gazelle from the Minx at the rear. Singer gained a twin carb engine and a new gearbox together with a deeper windscreen given to all Audax cars.The Gazelle Series IIIB came a year later with a new rear axle and a single carb engine. In July 1961 Rootes began marketing the Gazelle Series IIIC, a car that was never meant to be. A new 'Series IV' Audax model had been developed but was too costly to replace existing models, so the Audax models had to have their life extended in order to continue and market beneath the more expensive new model. The Series IIIC gained the new 1592cc engine, but in 1962 the convertible and estate models were dropped. In August 1963 the Series V Gazelle received the same major restyling as the Minx, with a squarer back and a flatter rear screen, deletion of rear wings, new oval rear lamps, and this continued until autumn 1965 when the Series VI was launched. The final Audax Gazelle gained the 1725cc engine and a new almost rectangular grille with 'S I N G E R' spelled out above it. In January 1967 Singer announced the new Hunter-based Singer Gazelle (Series VII).