A few of those look oddly familiar. Countries the British have never sent soldiers/invaded/fought a war in...?
Although Luxembourg. And surely there would be more in South America and the Pacific.
You are right. I knew I had seen that map before.
The author of the book says that it is likely the british have had a presence in some countries (i.e Luxembourg and Mongolia) but it can't be verified.
South America and the Pacific would be covered by expeditions by explorers and parties raiding Spanish territories.