Sorry Harry, I don't know how to zip files but exclude one from compression.
Browsing this forum I found a program called
ePubPack which is meant to create proper epub files. But when I transferred these to my iPad these don't display either.
Looking in my epub/zip file the order of the contents is...
META-INF
OEBPS
mimetype
the order of the contents in the OEBPS folder is
fonts
images
content.opf
template.css
page1.html etc
This is driving me up the wall.