Originally Posted by ldolse
This is a long-standing bug/feature request in Sigil - it deletes the existing TOC and builds it's own based on heading tags. This is by design, but it's on the roadmap to fix it.
There are a variety of workarounds discussed in the Sigil forums.
thanks for super quick response - I will search sigil forums, unless you have a handy quick link.
I guess that I could eplode epub , back up toc.ncx, edit in sigil, save, re-explode, replace toc, but I'd also have to also remember not to change the file split structure.