These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Crowning Moment of Heartwarming - at the end of The Secret Island when Jack finds out that Captain and Mrs Arnold are alive and safe, brings them to the island and the Arnold family is reunited. Then Jack being adopted by Mr and Mrs Arnold.
Germans Love David Hasselhoff - St Clare's, called "Hanni and Nanni" in Germany, is vastly more popular there. There are several dozen ghostwritten sequels and interquels that fill in the gaps in Blyton's original stories, as she had only covered a few terms.
Even more notable with Malory Towers. The German Version is called Dolly and spans 18(!) books. After the end of the original Series, Darrell - called Dolly in the German Version - attends a school for young ladies located directly next to Malory Towers, marries a teacher after graduating, becomes a caretaker at her old school and gives birth to a little girl. Oh - and helps pupils in misery on a daily basis.
In France, The Famous Five and The Secret Seven, known there as Le Club des Cinq and Le Clan des Sept, were very popular Kid Detective series, as well as sworn rival series of French novel series Les Six Compagnons by Paul-Jacques Bonzon. All three series were best-sellers of the French collection Bibliothèque (Bibliothèque Rose, the aimed-at-younger-audiences section of the collection, for the Bylton series, and Bibliothèque Verte, the aimed-at-slightly-older-audiences section of the collection, for the Bonzon series).
They were subjected to an awful lot of Cultural Translation / Woolseyism though: everyone became French, and Brittany replaced Cornwall.
There are an additional 18 books written by Claude Voilier about Les Cinq. They have been translated into English. Unfortunately, while the original 21 novels showed the Five progressing through school years and ending up in their early 20s/late teens, Voilier makes them Not Allowed to Grow Up.
Once Acceptable Targets - There remains a controversy over the use of golliwogs in the Noddy series (in more recent TV adaptations, these are usually replaced with generic goblin-type creatures). However, Blyton fans have argued that this was just a cultural thing, given that Blyton's books also contain plenty of positive portrayals of black people (e.g. Five Go To Smuggler's Top and the Mystery series).
There's a black villain in the original version of The Island of Adventure, but he's portrayed as smarter than his white henchman.
Black characters do tend to have Amos and Andy accents, however.