The final batch of the class were later fitted with newly developed 'Coal Scuttle' bunkers. These bunkers consisted of a higher rivet line increasing the water capacity up to a total of 2,700 gallons allowing the locos to travel longer distances. The bunker was also designed to facilitate the movement of the coal towards the hatch in the cab, however ‘scuttle bunkers’ would only carry 5 tonnes of coal instead of 6. No.7200 is the only surviving loco of the class to carry one of these unique bunkers.