In Section settings set the Marker Reference to "First placed drawing of the viewpoint". There is also "first placed drawing of the selected view", not sure what the difference is. (Too many words muddle my brain). Different markers may have different options further down the settings too.
Thanks Stuart. I used Section Marker_NSC 10 and in Section Selection Setup I chose Mark Reference to: The first placed drawing of the viewpoint. Also - in Layout, Drawing Selection Settings, I chose Drawing ID: by view ID. This seemed to do the trick.