A 1943 Flea would most likely have been brown, SCC2. This is now Service Brown BS381C ref 499 but only in matt finish. Any gloss level dramatically darkens the shade, a peculiarity of this colour.
British built vehicles were never US olive drab. We had our own version which came into use in early 1944 but it is not the same as US olive drab even though it was called olive drab. Still available, though possibly a little darker than the wartime spec as 298.