Using the Google Earth plugin. Loading a kml placemark. The only difference between this page and the previous page (googleEarth_3) is the location of the kml file, which is now sitting in my google docs cloudspace, having been downloaded as a kml file from code.google.com.
This now works too, thanks to some excellent help from Fraser at Stack Overflow. The query string given at google Docs to locate the document needs to be adjusted so that the kml file itself is downloaded: /open?id=FILE_ID should be changed to uc?id=FILE_ID&export=download. Thanks Fraser.