Photograph: Lucy Mangan

Happy Roald Dahl Day! Did you know that Charlie and the Chocolate Factory will be 50 years old next month? Roald Dahl spent a long time working on it before it was published, half a century ago and in his very first version there were not five children who went round Mr Wonka's factory but 10! And even the characters we know from the book now all originally had different names – except the hero. Charlie was always Charlie, right from the very start.

Lucy Mangan is the author of Inside Charlie's Chocolate Factory which contains everything you ever needed to know about Charlie and the Chocolate Factory. Out now, priced £20 (Penguin paperback).

1. Augustus Pottle

Of course you can guess who he became! That's right – Augustus Gloop (the great, fat, greedy nincompoop!) But what about…

2. Miranda Grope

In Roald Dahl's first version of the story, she also fell in the chocolate river after disobeying Mr Wonka's instructions and went up a pipe too – but to the chocolate-covered Peanut Brittle Room instead of the Chocolate Fudge Room like Augustus Pottle. And in the second version she became…

3. Miranda Mary Piker

"How could anybody like her? / Such a rude and disobedient little kid!/So we said 'Why don't we fix her? In the peanut brittle mixer? Then we're bound to like her better than we did."

4.Violet Glockenberry

Violet Glockenberry became Violet Strabismus (which is the medical word for a squint) and then – ta da! – Violet Beauregarde

5. Herpes Trout

Who was Herpes Trout? He was the original TV-mad boy we now know as Mike Teavee.

6. Elvira Entwhistle

And who on earth was Elvira Entwhistle? She was the spoilt young madam who wanted one of Wonka's trained squirrels until Dahl changed her name to Veruca Salt. He told Julie Dawn Cole, who played Veruca in the first film of the book that she was a wart of a child and a wart on your foot was "the very nastiest I could think of".

7. Tommy Troutbeck

Tommy Troutbeck - later Henry Trout – got taken off to the Pounding and Cutting Room after climbing into one of the wagons carting away lovely fudge from the Vanilla Fudge mountain in the first and second versions Dahl wrote of his story.

8. Wilbur Rice

Wilbur Rice went with the above mentioned Tommy Troutbeck.

9. Clarence Crump

In the first version, Clarence Crump, Bertie Upside and Terence Roper all overheat when they stuff themselves with hundreds of warming candies. You're only supposed to eat one!

10. Whipple-Scrumpets

Can you guess who the Whipple-Scrumpets were? They were the Oompa Loompas, until Dahl changed their names at the very last minute.

• Inside Charlie's Chocolate Factory is available at the Guardian's bookshop.

• Find out more about Roald Dahl Day and what's going on near you on the official Roald Dahl website.