So I published my third book and forgot my own rule. Formatting went to pot. So I have taken it down and re-edited it.
Remember folks, save your file as an HTML.
ie. Go to 'File'. Choose 'Save as webpage'. Save to somewhere easy to find such as in your book's component folder. Then go to the kdp page and your bookshelf. Select your book by ticking in the box next to it. Choose edit from the drop down menu. Replace the all-over-the-place file with your nicely formatted book (html you just created). Save and continue. Select the 'yes, I agree to hand over my first born child' on the KDP agreement. Save and there you are!
Hope this is clearer than my first explanation!