Would it be possible to have the chapter number (1.1, 12.4) next to the story map button? I know it displays it when you go down but that small text could help people find it quickly.
This sounds like a very useful suggestion. Considering how often I scroll up to check the chapter number before going back down for the story map, I'm surprised I didn't think of suggesting something like this myself.
Maybe it could be displayed next to the chapter/node options just above the story map, or next to the find-in-map icon you mentioned.
I'm not sure how useful that would actually be. If you have the chapters 2.1 and 2.2, both with child chapters, the first of them will both be numbered 3.1. (The actual Suggestion forum is a subforum of Site Feedback.)