How to null LeadEngine WordPress theme

The null is in the keydesign-addon plugin rather than the main theme. Edit the file wp-content/plugins/keydesign-addon/theme/admin/views/keydesign-envato-api.php. Straight after line 8 which is:

if(isset($_POST['purchase-code'])) {

add this code:

update_option( 'keydesign-verify', 'yes' ); wp_redirect(admin_url( 'admin.php?page=leadengine-dashboard'));
exit;

Now you can use any key to activate the theme.