No, Churchills were also used in Tunisia -well, that IS North Africa, but the photos you're thinking of were of the few "King Force" Churchills painted in that camo scheme. See "Mr. Churchill's Tank", by David Fletcher -it's excellent! Normally the majority of Churchills were the standard green. Of course, being B&W photos, we don't know if those King Force tanks were black/sand or green/sand. If you have more references, please share.