Hi James,

The problem here I think stems from the roles of positional manager ie the actual manager of the staff, and the site-wide role of Staff Manager. At present in order to mark course as complete the manager must be assigned the side-wide role of Staff Manager. This can be done under "Roles" in the profile settings for the manager in question. 

To mark a course as complete its best go into the Course completion report

Home>Courses>Reports>Course Completion

Hope this helps,

regards,

George.