Many thanks for the response, unfortunately I still can't get it to work.
I've placed that code just before...
// WA Application Builder Update
if (isset($_POST["updatedriver"])) // Trigger
But when I then try to use the page and hit UPDATE it refreshes the page, doesn't remove the filename and displays a warning message at the top which reads...
Cannot modify header information - headers already sent by (output started at /../../../../admin/updateadriver.php:105) in /../../../../admin/updateadriver.php on line 150
In my file here, line 105 is the opening <?php of the code you suggested while line 150 is header("Location: ".$WA_redirectURL);
If it's any help, the trigger I am using for the regular update server behavior is a button named 'updatedriver'.
I would be very grateful for any further assistance you can offer.