Synthesized answer
The provided passages do not contain information about the evidence the author provides in "My Early Life." The passages only mention the title of the American edition [1].
Synthesized from the book passages below. Chat with the book on Feynman for follow-up.
From the book
Title: My early life by Winston S. Churchill Description: American edition (New York, C. Scribner's sons) has title: A roving commission; my early life.