I have a policeman ancestor, James Weaver, a metropolitan policeman between 1861 and 1882. It may not apply in this case but I have had a lot of joy in searching for him in newspapers databases. Because I have his number, 82 S, I have been able to find him in three articles in The Times and twice in two other newspapers, usually as a witness in hearings or trials. I have also found him as a witness in an Old Bailey trial as they have computerised their archives.
So you don't just have to rely on the police records.
As an aside, does anyone know if there are metropolitan police photographs from this period? Of course I'd love to find a photograph of him but I know that's probably a fantasy. But I would like to see how policemen looked at that time.
Gareth