It is a Canadian Military Pattern (CMP) Tractor/Truck pulling a 25 pounder gun. This is one of the types of vehicles/guns that my own Grandfather used in WW2 with the Royal Canadian Artillery.
I have the Tamiya kit of this to build in his memory and when I do I will detail that on this site (I also have the Dragon Kit of the M7 Priest that he used on D-DAY to build).
I hope people find this useful - and if they do I hope they will share photos of/links to their work.
NOTE: CLICK THE LITTLE "EXPAND" BUTTON IN THE BOTTOM LEFT HAND CORNER TO PULL UP THE FULL PICTURE SET