Guns
Great article, putting Quatermass into its historical milieu. However, I take some issue with the comment "Their machine guns sport a drum magazine and look a lot like the Red Army's PPSh-41". From the still on page 1, it is fairly clear that it is a Thompson sub-machine gun with a drum magazine, well known to British viewers in those days as the weapon of choice for gangsters (often carried in violin cases for some reason). It would be good to be able to read more into that, but is is probably that the props department had plenty of them lying around.
Equally, the helmet in that still looks more like those worn by GIs in WW2. I'll leave others to talk about the predictive powers of Nigel Kneale, and whether he should be nicknamed "Nostradamus" ...