Tim,
I have a page on Divisional vehicle markings for a Canadian Signals unit here:
http://www.rcsigs.ca/index.php/Vehic...sional_Signals
Unfortunately it doesn't have a H6 listed and says that the markings would be Artillery based. I see now that I didn't record where I found this info or what date it was effective so perhaps this was after the time of your pic. I will go hunting for it and any other info again.....
From the darkness of the Div patch, my guess is 2 Canadian Infantry Division. 1 Div was a red colour which I think would show even in the b/w picture and 3 Div was a French Grey colour, again it would show lighter I'd say.
Cheers,
Joe