Great photo of the Fort Beausejour tank lines, Jason. I count 45 Centurions in the picture, which would put the date it was taken sometime between 1957 and 1962. The regiments stationed there during those dates were The Royal Canadian Dragoons followed by the 8th Canadian Hussars (Princess Louise's).
Note that some of the gun barrels don't have a fume extractor, while not all have a counter-weight on the muzzle. Finally none of the vehicles have been painted in a camouflage pattern.
Again, great photo.
Cheers,
Dan.