You don't need to edit any of the source files to change the site name. Log in as admin and go to "Front Page settings" (see attached screenshot).
However, if your site administration menu is missing (is that what you mean by "the usual front page link is missing"?) even though you're logged in as admin, I suggest you try to find out why it is missing rather than edit the source files.
However, if your site administration menu is missing (is that what you mean by "the usual front page link is missing"?) even though you're logged in as admin, I suggest you try to find out why it is missing rather than edit the source files.
