 Following their appearance at the Commercial Motor Show in November 1927, they had received an order from Doncaster Corporation for four 3-axle 60-seat vehicles.The first one to be completed was tested on the Mexborough system in March 1928, although it was unregistered at the time, and ran using trade plates.As the system expanded in the late 1920s, 30 Garrett type O vehicles were purchased between 1928 and 1930.