Your thread title 'Section numbering screwed up' implies something to do with Section breaks & headers, for which I took your reference to heading 3 not continuing on from heading 2 to be a reference to header content, not to the Styles named 'Heading 2' & 'Heading 3'. It would be easier to provide help if you expressed the problem with greater clarity.

If you start by defining the Heading Style multi-level relationships with 'Heading 1', working through all required Heading Styles systematically, all of the Style deinitions will be updated automatically without the need to select anything other than the initial paragraph with the 'Heading 1' Style. Furthermore, there will be no room for any of them to go awry part-way through your document unless someone has overridden the Style-based formatting with hard formatting at some point. Even then, however, it is only the overridden paragraphs that will be affected.

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Cheers,
Paul Edstein
[Fmr MS MVP - Word]

To add to what Paul has said, when editing heading numbering, click in the first Heading 1 paragraph of the document and then click Home | Multilevel List | Define New Multilevel List. Set up numbering for each level and verify that heading styles are assigned to their corresponding numbering levels. For details, see http://www.shaunakelly.com/word/numb...g20072010.html.

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Stefan Blom
Microsoft Word MVP

Microsoft 365 apps for business
Windows 11 Professional

Thanks all for the comments and for that link. I am going to read through that article in detail and try avoid these issues in the future. Unfortunately the template we have been used is beyond repair, too many cooks copying and pasting from other documents which seems to ruin things and add far too many styles into the equation.

What you have appears to be something described by the technical term "spaghetti numbering."

Sometimes what is needed is to copy the entire document's text into a new document as plain text. Then apply appropriate styles to format it.