OK - Sorry - Found out how to do it now - very sorry.
INSTRUCTIONS
Files to edit
/admin/login.php
/admin/index.php
Files to add
I think it's best to have a different name for this favicon as it is not the storefront or default - so what I've done is - as per the examples below - used the name adfavicon.ico and placed this icon in the admin folder.
in login.php
under this line:
<link href="includes/stylesheet.css" rel="stylesheet" type="text/css" />
ADD THE FOLLOWING
<link rel="icon" href="<?php echo HTTP_SERVER.DIR_WS_CATALOG; ?>/admin/adfavicon.ico" type="image/x-icon" />
<link rel="shortcut icon" href="<?php echo HTTP_SERVER; ?>/admin/adfavicon.ico" type="image/x-icon" />
--------------------------------------------------------------------
in index.php
under this line: (same as before)
<link href="includes/stylesheet.css" rel="stylesheet" type="text/css" />
ADD THE FOLLOWING (same as before)
<link rel="icon" href="<?php echo HTTP_SERVER.DIR_WS_CATALOG; ?>/admin/adfavicon.ico" type="image/x-icon" />
<link rel="shortcut icon" href="<?php echo HTTP_SERVER; ?>/admin/adfavicon.ico" type="image/x-icon" />
--------------------------------------------------------------------
Hope this is useful!
Thanks Zencart Team!:smile: