Page numbering problem with formatted document

Thank you.
No, I don’t want to set a different page style except to get a page number, centered, at the top of most pages. The margins are all set as required for a paperback.
Since posting my question, I’ve tried using style->styles and formatting->page number and then insert->field->page number and then line break and that seemed to work for some pages - but on others, the formatting of the following paragraph was all messed up again. I tried it again after using format->clear direct formatting on the offending paragraph but that didn’t work either.

Presumably other people have done this before, so I must be missing something - but what ?


It would be helpful if you add an example of the desired layout. Check my other, updated answer.
And please, comment on answers instead of posting a new one.

I’ll try to add a link to a screenshot of a sample page - without the top, centered page number. Not sure how this works though. Clicking the “link” icon doesn’t work though. How is it supposed to work ? I have a jpg of just over 100kbs to send.

Here’s a link to a sample page, again without the desired top, centered page number.
All formatted and displays correctly as an ebook.