Try Amazon. Lots of them but I have not read one. Some reviews are quite revealing. https://www.amazon.com/s/ref=nb_sb_...ield-keywords=Battle+Of+The+River+Plate+books
There used to be a really good account on line titled something like "The Raiding Cruise of the Admiral Graf Spee". I had it bookmarked but the link isn't working and google doesn't find the site.
What i want to know is the name of the sonny boy who named it "River Plate." "Plata" is silver in Spanish. Some Spanish-speaking people call their dining plates "platos" is all.
Unsure as to who the exact person was but the English name of River Plate was in use from the time of the visit by Sir Francis Drake in 1578. The word had then exactly the same meaning ; 'Plate' in Early English was used to describe silver or gold.
I was just down in Montevideo at the cruise terminal...when you walk out into the city the first thing you encounter is the Spee's main rangefinder and other assorted "memorabilia".
We anchored out there in the '70s. The CO said we were exactly where Graf Spee was scuttled. The boatswain mates said we'd put out too much anchor cable to be that shallow. But they didn't say that to the captain.
34º 58' 18" South, 56º 17' 57" West about ten miles or so southwest of the old city. So I doubt you really anchored there.