In the email template file, the code that generates the time in the email is:
<?php $now = time(); ?><?php echo date("n-j-Y", $now); ?> | <?php echo date("g:i A T", $now); ?>
change that code to:
<?php date_default_timezone_set ("Europe/London"); $now = time(); ?><?php echo date("n-j-Y", $now); ?> | <?php echo date("g:i A T", $now); ?>
to change the time zone.