[Quoth]

Originally Posted by kovidgoyal

Conversion of heading styles to <h> tags works fine provided the heading styles are named Headin 1 Heading 2 etc. See the demo docx file at
https://manual.calibre-ebook.com/con...word-documents

Yes, I'd concluded that. Perhaps I didn't make it clear I'd tested that also.

Thanks.
(Also you are either up late or very early!)

But that doesn't work if you need different styles at the same heading level.

So for now I'll have to edit the final epub, which I have to do anyway to tidy up image CSS

The <p tags with correct style and TOC & page breaks for headings is fine for proofing, beta readers etc. The actual <hx tag is only needed for semantic purposes, like perhaps TTS, because the TOC structure, layout/format/style and page breaks and appearance are all fine. Identical in fact!