Therein lies my problem, as the long-press on set file was the first thing I tried, since it is the most intuitive thing to do. Unfortunately, the menu displayed does not include "Edit Points". Remember this file is a "Set Of Waypoints" rather than a route, so there are no points to edit
Using the cut / paste method, I receive a Java error at the point where I paste from the clipboard... Class: BCM, Null object reference.
The + button option would probably work, but it is of no use since it is not selecting a point from the map, it just prompts for a name and assumes you know the co-ordinates (which I don't).
The last option is the one that works

I had tried something similar, but was selecting "Create A Landmark", rather than "Waypoint". However, the trick that I missed was pre-selecting the set file in the explorer.
Although this method does work, it all seems overly complicated, even to an experienced AQ user like me. What I was really expecting was to be able to long press the waypoints set name and then select an "Add Waypoints" option, similar to what you described for route files. Having selected "Add Waypoints" I would expect the app to enter the same mode as when selecting "Create Set Of Warpoints". Does this make sense?
*** EDIT ***
After a bit more experimentation I discovered that clicking on one of the waypoints on the map itself and then picking the set file name from the context menu, does produce a dialog that does have the "Edit Points" option on it! Moreover, selecting "Edit Points" does put AQ into the same mode as "Create Set Of Waypoints" ... exactly what I was after in the first place
So all we are dealing with here is a small ommission on the menu shown when performing a long-press on the set name within Landmark Explorer (ie. the "Edit Points" option is missing). Plus the Java bug, of course
