Plotting a Novel

Here is my tried (and tried and tried) and slightly tested method for plotting a novel.

1. Have a brilliant idea for a story. Play around and see if it's still a good idea for a story a week later. Hopefully it still feels slightly interesting by week 2 after which you will begin to lose hope.
2. Taking little coloured cards, map out scene by scene, your characters' journeys, different colours for different characters' POVs.
3. Sit down with card one and write the scene, allowing it to veer a tiny bit from the plan, but that's OK because you can modify card two. Which then means cards three to six need modifying and cards 6a and 6b need to be created.
4. Write the scene from card two,trying to keep it on track even though it wanders wildly down a much more exciting path and your character turns out to be a lot bigger and bossier than you expected.
5. On card three discover that your second hero character is actually the antagonist. throw cards away.
6. Write completely unplotted for 45,000 exciting words, following a rollercoaster of an adventure. Some bits are wild knuckle rides, some bits are look-out-at-the-view and eat your sandwiches. A few bits are sit-quietly-twiddling-thumbs and have no tension at all.
7. Rush for the ending which has eluded you, but it now seems inevitable that the protagonist gets eaten.
8. Rework the last 20,000 words so the antagonist doesn't get eaten, but now seems that the protagonist will have to eat the antagonist. This wasn't supposed to be that sort of book.
9. Scrap whole book. Go and sign up for an MA so you can learn to plot. Start writing again but slower.
10. Start MA and tart up a few chapters. Realise they are hopelessly unpaced.
11. Rope in eldest son (mine) to write a synposis broken down by chapters. You will  immediately see the wallowing-in-the-doldrums middle chapters.
12. Use Vogler's mythic structure to loosely map more rising tension. 
13. Get some white cards (is this the magic trick to plotting?) and put each scene on one.
14. Organise into some sort of sequence and into chapters. Highlight wallowy scenes.
15. Rewrite synopsis from white cards (which I'm sure are significant) moving them around and bringing the tension up. Explaining the loose ends and pruning out others before they even start.
16. Cut out two small characters completely. One of them will have to be rewritten in when you realise the ending doesn't work without them.
17. Make the ending much, much bigger.
18. Throw magic white cards away (this might be a mistake) because the story has moved on. You now have a chapter by chapter and scene by scene plan for the book in about 25 pages. You probably realise how many words of prose you could have written in the same time...

I am optimistic that I have something I can write from, anyway. At least if I write scenes I can just move them around and my first draft gave me a clear picture of the characters. It can't be worse than getting to the two thirds of the way in a book and realise you are completely lost.