Hi Daren,
There were three different tanks fitted to the Mark series machines. According to the spares book, the single tap tank was fitted to Mk1 machines. Mk3 Sports had a tank with twin taps below the knee pads. Mk3 machines may have had either tank.
With the repositioning of the toolboxes on the Mk4, Mk5 and Plus machines, the taps were moved to the rear of the tank. these later tanks also had a modified front mounting lug with three holes so that the height could be adjusted.
Hope this helps,
Eddie.
