[Trooper117]

Having gone through this discussion several times, I'll bring it up here.. 3 or 4 years ago I was at Duxford and got talking to an old Aussie flyer who was viewing the Beaufighter under restoration, a Mk21 no less.. We had a brief chat for 5 mins or so, but he left me in no doubt that the Mk21 could be fitted with a vickers K for the observer at the back... Alot of the time they were not mounted because at that stage of the war the threat from Japanese opposition was virtualy nil (in the air)..
Early Mk21's did not have them initialy but later Mk21's did have them.. (Bearing in mind the Mk21 was an Australian copy of the English MkX, and didn't enter production until 1944)
By the way another point he brought up was the Sperry Auto pilot in the bulge at the front was rarely carried...