Hi Anne-Marie. Copying and pasting the Word doc into ID brought those hyphens in as ordinary hyphens (don’t understand why but at least I was able to get on with the layout!). Placing the Word doc deleted them. After a couple of lovely people on the InD google group replied (within minutes) with suggestions, I opened the Word doc and hunted in the Advanced Find and Replace > Special and found nonbreaking hyphens (amongst other sorts of hyphen). This gave me ‘^~’ (without quote marks) which I copied and pasted into the Search field of the doc, asked Word to highlight them all which it did, and actually replaced them with an n dash.
Regarding the earlier four books (which were so long and tedious that I hadn’t noticed the missing hyphens), the import into ID missed out hyphens between words as well as numbers, so I’ll just have to pay attention to Word documents a bit more, although the publisher sends files fairly frequently and there’s little time for refinement!
I had already tried saving the Word files as .docx but that made no difference at all. There are several places on the web that describe Word version 7 as having this problem (on import into ID although I’ve stopped at CS6 and the CC versions may, of course, be able to cope) and that MS had, at some time, issued a patch — but I’m not convinced that all five authors use v7 and they certainly don’t understand what I mean about the patch! Sigh!