I found this website today, https://www.britishbattles.com/ It has detailed articles on battles from 43AD to 1916. Recommended

@Jamie Birch welcome to the community. As you can see, it's been on the back burner a bit, but I look forward to chatting with you

A British soldier leaning against a jeep. He's a corporal, possibly a sergeant (the armband may be covering a third stripe (chevron). The cap badge is very helpful by it's shape, despite the poor detail in the image. The armband helps to identify the cap badge. The armband is a Military Police band, which was always worn on duty, and was a red MP on a black background, which is a good example of the detail that is lost in a copy of a copy of a black and white image. The badge is Royal Military Police. The jeep can be identified as British, post WWII, by the tiny light on the wing above the wheel. These were fitted from 1949 onwards. There's little else that's useful, except that I know that this is my Dad in Malaya at the start pf the Malayan Emergency, so I've cheated a little. I've "back-engineered" this image to show the little details that emerge when you look closely. BTW, he swore that was a cup of tea in his hand, not a drink!

And in the cover image, is my wife's ancestor Thomas Henry Nairne, from the tiny town of Borambil, New South Wales. Killed in action in 1917, he has no known grave and is commemorated on the Menin Gate. This photo was found in the shed of a relative. Note Stonehenge in the bottom corner, indicating this image was taken in Salisbury, during training. These are the details you need to spot to decipher the clues.