[Glider]

Kurfurst
Its late but I will comment on another of your points namely

The fact that the vast majotity of the fuel consumed was steadily 87 octane until the end of September 1940 (in agreement with Pips)

The important thing is the noticable increase in 100 Octane in September. Unfortunately we only have an average consumption figure for June to August of 10000 tons a month. I would expect the August figure to be very similar to September.

There is little doubt that the consumption of 87 Octane was broadly similar until the end of Sept 1940 (Paper Attached) but I wouldn't have expected anything else. The Other Commands were not given clearence to use 100 Octane until August 1940 (Paper attached) and it would have taken a little time to move the quantaties of fuel around.
In fact its noticable that in September the usage of 87 octane fuel started to fall despite the intensity of operations. The overall consumption figure, (combined 87 and 100 Octane) for August is almost identical to September 36,000 tons vs 37,000 tons but the 100 octane is going up and the 87 Octane down.

Remembering that the policy for the replacement of fuel in No 2 Group was to replace empty 87 Octane tanks with 100 Octane, the immediate effect would be little difference in the consumption of 87 Octane in late August / early September as the tanks are emptied, but a significant increase in the proportion of 100 Octane issued, to refill the empty tanks.