The BBMF one is shown in a large poster image and has a top view showing what appears to be 2 square-ish holes in the top of the fuselage between the top turret and the main cockpit... which the Canadian one doesn't appear to have .....
So.... oh great and venerable ones...... what pray are these 'holes' ... my meagre brain has worked out that perhaps they may be hatches of some kind - but if so what purpose do they serve in flight - as when flying surely they would let the sky in ....very noisily.... or blow away the navigators maps.... or some such
And on this one there's only one such 'hole' - and where the other one 'was' is what looks like a hatch cover - so my hatch theory begins to hold water ......but why hatches there - and why open in flight ?
