I have a funny feeling that these were originally VB gun boxes and it was a case of utilising these for all as opposed to making them especially. They had VB's long before they had Brens. On the other hand, maybe we continued using the original long box because we didn't see any point in having a mixed fleet. Or, maybe common sense prevailed and someone high up the food chain in the Ordnmance world thought about making short ones until someone whispered in his ear '............ if it ain't broke, then don't fix it....!