@JosephWright meanwhile back on github, I have to decide how much I like the next/previous links and whether to push for them upstream..... they work (see
next here
davidcarlisle.github.io/texfaq.github.io/FAQ-startup ) but they have a big impact on build time as seems there is no global state so you have to harvest the list of files and essentially generate the full table of contents ordering on each page.