For example: This leads me to believe it was written by an American.
the English public became involved in a way never before seen in warfare:
Nothing wrong with that but Americans commonly confuse England with Britain or vice versa. While most of the action took place over Southern England the threat was to the whole country which is the reason it's known as the Battle of Britain. The RAF fighter pilots came from all over the British Empire & other parts of the world including the US.

PS.
In the spring of 1940 the Third Reich was the largest Empire the world had ever seen.
I'm not sure about that. Forgetting the ancient empires, in 1939 the British Empire covered something like 1/3 of the world's land mass. It was still much the same when I was at school in the 1950s.

The problem with many modern historians is that they base their ideas & arguments on modern concepts. To get the complete picture you need to try & appreciate the way things were at the time they occurred. This can be difficult for anyone not there at the time as life for ordinary people (including their outlook on it) was often very different to what we're familiar with now.