what happens when you File > Package and thereby gather fonts into a Document fonts subfolder?
They are all there, because I've re-found them.
Problem seems to be solved by using 'open original' and playing around with 'find font' setting. But new problem is when people copy the file to use it they are all missing. Even though they all have the fonts installed too. Am going to get them to do what I've done as above to see if that helps. It's a template for 5 people so needs to work :-)