Thanks for your considered response which I found interesting.

It didn't quite answer my questions, and just in case anyone in the future has a similar issue to mine, I discovered that I needed to change the view back to print layout rather than Weblayout (accessible in the View tab). Because I was in Weblayout when working on it, it retained that setting whenever I opened up a new Word document.

In relation to your other comments, yes, I would love to have had the original PDF's but unfortunately I am dealing with more than 9,000 pages (four times the size of a bible) of typed content from the 1980s, so not much chance of that.

I've been saving it as an RTF file, but the next step when I finish checking all the OCR will be to try and find a good way to convert it all to HTML that retains most of the Word formatting. I've been using Convertio but I'm sure there are better options around.