Still trying to get the size down, I know that a lot of it is because there are a load of illustrations. Most of them started up as BIG images, and were resized when I pasted them into the original Word document.
I've been assuming that this works like saving a print file - the final file size in the PDF is based solely on the area of the picture and the resolution of the PDF, and not the picture's actual original size, so that if (for example) I used the same picture at two points, one full size and the other at half size, the size added to the file will be much less for the smaller version.
If I'm wrong then I suppose I have to resample all of the pictures to their final size before converting it to the PDF, which will be a lot of work. Does anyone know for sure how this is supposed to work?
Later: Tried Adobe's "free file conversion" thing. It wouldn't even start to upload the file, let alone let me enter the parameters. I suspect that they are expecting dainty little things, not a complete book!