Thanks to Lyric1 for finding me the info for this skin.
The 1st Polish Armoured Division was formed in 1942 from Poles who had fled from the Nazis, first to France and then to Britain. It first fought in 1944 during the latter stages of the Battle of Normandy where it helped close the Falaise gap, cutting off the Wehrmacht units encircled there. Later it fought on through Holland and into northern Germany.
This M16 was part of the Division's 73rd AAA Regiment and featured British Army style markings denoting its company and platoon etc. It also had a British Army camo scheme that attempted to disguise the shadowed areas of the vehicle around the wheels and tracks by extending them with with areas of black circles. Previous British Army schemes had tried the same disguising trick by painting the shadowed areas under the vehicle white.