Back to the portrait photo of your father in his 1st Armoured Division battledress, another tidbit of info for you.
Although itís bit tricky with the black and white photo, the pennon shading looks right for the black/green of the 1st and 2nd Motorized Artillery Regiments. Posted below is a picture I quickly snapped of a motorized artillery BD and converted to B&W along with colour adjusting to approximate the sepia tone of your dadís photo. You can see for yourself that the shading looks spot on. The pennons on this surviving BD also have a distinct cut and size that matches very closely to the ones on your dadís uniform.