When creating a test store for developers to work on you should clean down any customer data for privacy. This will stop data theft and you getting fined. To do this create a file in /admin/ called delete_all_customers.php

define('IS_MULTILANGUAGE', 1);

require './auth.php';
require $xcart_dir.'/include/security.php';

x_load('backoffice');

		
$customers_sql = "select id from $sql_tbl[customers] where usertype='C' and login!='email@toexclude.co.uk' limit 5000";
	
$customers = func_query($customers_sql);

if (is_array($customers)) {

	foreach($customers as $c) {
		func_delete_profile($c['id'], 'C', false);
	}

}

echo "<pre>";
print_r($customers);
echo "</pre>";


die('end');

This will delete all customers except for the one with the email address email@toexclude.co.uk. Limited to 5000 at a time. Just run it multiple times until all gone.