Thanks Dave - very thorough and extremely useful.
I'm hoping to get to the Leicester record office once lockdown lifts as they believe they may have additional photos of my relative.
I do have one photograph of him in Uniform from c.1876 when he was a PC - It looks like the badge he is wearing is similar to bottom right of your first photo but with a Queen Victoria crown - hopefully one of these will pop up at some point!
Here is a link to the photo in case it is of interest -
Link. Thanks as well for the book recommendation - I'll be sure to take a look