Although primarily issued to the 3rd Canadian Infantry Division, and not to the whole division but to what appears to be only the assault formations, the British MkIII Helmet was also issued, in limited quantities to other non 3rd Division units. There are photographs of 2nd Canadian Infantry Division and 4th Canadian Armoured Division personnel wearing the British MkIII Helmet in NW Europe. As with most things military, there are no absolutes, so it should not come as a surprised that MkIII Helemts were used by other non 3rd Division formations, BUT IN VERY LIMITED NUMBERS.
Now all of you 2nd Division re-eanactors do not have to starting squirreling away the kids milk money for a MkIII Helmet. Much like the can of worms that was opened by the 1 Can Para re-enactors with the M1 Garand Rifles and folding stock M1 Carbines, MkIII Helmet use in 2nd and 4th Division units was not prolific enough to demand that you run out and purchase a helmet for wear. As well, the photographs seems to indicate that re-enforcements were using the MkIIIs and not the old sweats.
Also, the MkIII Helemt was standard issue to British units from 1945 until the 1980s, so to encounter one with a red hackle painted on the side could very well originate from an Imperial Black Watch Battalion and not Canadian sources as we would all like to believe.