Network Admin Email changed, but still sending from old address

Hi there,

We've changed the Network Admin Email address to a new one, but when a user changes their password, the confirmation email is still being sent from the old email address.

We've checked in class_phpmailer.php but the relevant code is still the default:
/**
Sets the From email address for the message.
@var string
*/
public $From = ‘root@localhost’;
/**
Sets the From name of the message.
@var string
*/
public $FromName = ’Root User’;

We're using SMTP v1.1.2 for the mail service, but there's no settings there to change the from address.

Any clues on what to do next?

Thanks

Allison