Set compression quality to Auto/minimum. PDF is still 22Mb, and it's set for screen/web. Only using one font, with variations (light, bold) which come as a single font package. Changing embedding to outlining seems to have no effect on the size.
I did a test document with all the font variants in, and that comes out nice and small, so I suspect the images. After pre-compression, largest image is 370kb. So, a bit bewildered.