Thanks to your advice I am almost there! Words and pictures are now all in the right place and the book is now in Mobipocket Creator complete with cover, metadata etc.
However I used Comic Sans (size 12) when I wrote the text in MSWord but when I preview it in the Kindle Previewer it looks like Times New Roman. Have I done something wrong? I am not too worried if it can't be altered but as it's a children's book, Comic Sans is easier to read.
Thanks again, Jayne