Building a model of the Grant CDL tank. Building a British one so my question is what colour do I paint the tank in. US olive drab or did the British use a different colour?

SCC 15 olive drab. The CDL was a British invention. It was first used on the Matildas (300) then on the M3 series (335) the lees were various marks M3, M3A1 and I think M3A3s. They were a big secret weapon.