So you are going to deny that the film I supplied is not in fact making a turn at over 370 mph??
it is kind of critical to my first statement that started this 
No, and I never needed the film, nor have I watched it, as I knew what you were describing. You are converting a small amount of the aircraft's power into a slight turn, essentially using the excess power at 360mph to turn. The Spitfire Mk VIII, not able to go that fast, has no excess power to convert to a turn at that speed. I am assuming the tests are on the deck.
That is not a test of an aircraft's turning capability, it is a test of its speed capability. Any aircraft that is faster, no matter how poor it may be in terms of max degrees per second turn rate or minimum turn radius, would be able to do that in a test against a slower aircraft. It has nothing to do with the aircraft's ability to turn.