Re: No brainer shirley?
I think most of those transport cafes in those days learned their tea making skills in the military. When I was in the army ( much later), when out on exercise, sometimes the catering corps would come out with 'lunch' ( stuff in large aluminium trays), the tea that came with lunch was in a bowser that was was heated to boiling then a large bag of army strength tea bags was thrown in with a bag of sugar and a bag of army powdered milk.
After having been run aroung the British countryside carrying a rifle, lots of blanks and smoke grenades, spare ammo for the machine gunners and anything else a training sergeant could think of to load you up, for 24 or more hours without proper sleep, army tea tasted good and in those days I was a coffee drinker.
For normal times and places though, anyone who mixes the ingredients all together in that way should be lightly killed and told not to do it again.