As a child, I was a big fan of Enid Blyton and grew up reading the Famous Five, The Five Find-Outers etc.
The book that I am aware of being "cleansed" is the Island of Adventure where, originally, the perpetrator of evil deeds was a black man called Jo-Jo. He is now apparently a white man called Joe in newer editions.
Now, two things struck me about this. Firstly, as a reader of the book at a young age, the fact that he was black barely registered with me. All I knew was that he was the ringleader of the baddies who were counterfeiting money in the old mines on an island and this was all that was relevant when I was 8 years old. It seems to me that it's adults who get worked up about this sort of stuff, not the children that the books are aimed at.
In addition, there were 21 original Famous Five books, 8 in the aforementioned Adventure series and 15 in the Five Find-Outers series. That's 44 books. Now, if i recall correctly only one had a miscreant who was black. It therefore seems to me that perhaps Enid Blyton's writing might not actually have been the evil pinnacle of white supremacism that it's being made out to be by some delicate souls.