Quoted half a pint of free milk daily provided to all pupils under the age of 18 in state schools across the United Kingdom That's generous. In OTL it was only a third of a pint. I can remember in winter the bottles being frozen solid when they were taken in from outside and then put on radiators to thaw them out. The warm milk tasted vile, and was probably at the optimum temperature to encourage the breeding of bacteria. Ah, Schooldays, the happiest days of your life.
I wonder what Peter Fleming's younger brother is doing in Wesworld. Did he become a Commander in Naval Intelligence like he did here?
I think it's what's in the cartridge rather than the length that makes the difference between 'British' and 'Parabellum'. Britain was using cordite as a propellant and just about everyone else was using nitrocellulose. IIRC, this is why the gas cylinder on the Bren is shorter than on the ZB26 family.