I saw the Midge flying at Farnborough in the 1950's and my memory of it is the middle shade of blue as shown in Andy's link and definitely not the light shade. I doubt if there are many people who will be able to argue against it from a sound base any way. My model of the Swift is the wrong shade of blue but I had painted before my recollection of the actual aircraft colour had come back into focus, too late then. My colour memory doesn't usually let me down but in any case not one person has ever commented it upon it!
Looking forward to seeing your model coming together.
Yes, I saw that discussion, and as you say, it's not conclusive.The photos below can be found on internet, but they vary from deep blue to light green, so it seems to depend on the aging of the original, and the scanning parameters.