Thanks very much Stefan.

There is no (obvious) indicator as to what it is, so you don't even know where to begin searching.

Seems like an option is needed under the controls section for "Unwrap content" or some such rather than the to do the double save.

I'm guessing that when going from .docx to .doc there is the possibility that there might be some other formatting that could be lost.

But for my situation your solution without doubt fixed my problem.