@PatClay

My file includes/languages/english/modules/payment/dirbankaus.php (minus the header..):

Code:
 
  define('MODULE_PAYMENT_DIRBANKAUS_TEXT_EMAIL_FOOTER',  
  "Please use the following details to transfer your total order value:\n\n" . 
  "\nAccount No.:  " . MODULE_PAYMENT_DIRBANKAUS_ACCNUM . 
  "\nBSB Number:   " . MODULE_PAYMENT_DIRBANKAUS_BSB .  
  "\nAccount Name: " . MODULE_PAYMENT_DIRBANKAUS_ACCNAM .  
  "\nBank Name:    " . MODULE_PAYMENT_DIRBANKAUS_BANKNAM . 
  //"\nSwift Code:   " . MODULE_PAYMENT_DIRBANKAUS_SWIFT .  
  "\n\n<b>Thank you for your order which will be processed as soon as we have received payment in the above account.</b>\n"); 
 
  define('MODULE_PAYMENT_DIRBANKAUS_TEXT_TITLE', '<b>Direct Bank Deposit - Australia</b>'); 
   define('MODULE_PAYMENT_DIRBANKAUS_TEXT_DESCRIPTION',  
  '<div class="important"><br />We will email you our bank details for the transfer of your total order value<br />' .  
  //"\nAccount No.:  " . MODULE_PAYMENT_DIRBANKAUS_ACCNUM . 
  //"\nBSB Number:   " . MODULE_PAYMENT_DIRBANKAUS_BSB .  
  //"\nAccount Name: " . MODULE_PAYMENT_DIRBANKAUS_ACCNAM .  
  //"\nBank Name:    " . MODULE_PAYMENT_DIRBANKAUS_BANKNAM . 
  //"\nSwift Code:   " . MODULE_PAYMENT_DIRBANKAUS_SWIFT .  
  '<p><br />Thank you for your order which will be processed as soon as we receive payment in our account.<p><br /></div>');
Also try:

Code:
"\nReference:     " .$zf_insert_id .
instead of

Code:
"\nReference:     ".$zf_insert_id .
(note the space between " and .$zf_insert_id . )

Suggest you do a test order as customer using the codes above

Cheers / Frank