I have read that until late 1941 the color was an aluminum pant (tamiya's AS-12 rattle can works well).The change to gloss white was for the need to use the aluminum paint in the aircraft industry. But the change over was not completely done. Valentine tanks built 5 miles apart by two different companies at the same time had different interiors (one aluminum and one gloss white). Companies used up their stocks of paint before switching over. For example, there are pictures of Churchill Mk VII Crocodiles with aluminium painted interiors.
For vehicles in North Africa I would use an aluminium color for British made vehicle. Lend Lease would use American colors. As there isn't a truelly uniform timeline of departure from one color to another and also the depot time to get the vehicles to the field the choice may be up to the modeller. For example, all Matilda II's used in North Africa should have interiors aluminum colored, but those used in the Pacific and Burma amy be either of the two colors.
Here's Starmer's reference:
www.mafva.net/.../Starmer%20camo.htm
Mike T.
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