Yep. The towed bowsers were very big, around 2,000 gallons I think, with the bowser trucks bigger still. On Malta, the Spits were mainly re-fuelled from square, I think 4 gallon cans,not 'jerricans', by hand. These square cans were later filled with sand and used to make blast pens for the aircraft.
I'm fairly suer that's an oil re-supply cart in the diorama.