Hi Martin,
There was spacing difference between two.
Try adding following code, replacing existing one.
<div class="copyright">
<div class="aligncenter"><?php echo 'Copyright © ' . date("Y") . ' ' . get_bloginfo('name'); ?>, all rights reserved | Charity number: 801523</div><div class="aligncenter">Theme derived from the <a href="<?php echo esc_url( __( 'http://wordpress.org/twentythirteen','twentythirteen' ) ); ?>" title="<?php esc_attr_e( 'Twenty Thirteen Theme', 'twentythirteen' ); ?>"><?php printf( __( '%s', 'twentythirteen' ), 'Twenty Thirteen' ); ?></a> | Reworked by: Martin Rowan</div><p></p>
</div>
Regards,