Hola vitro012, acabo de probar lo que me has dicho pero me salta un error... te lo pego
Warning: Cannot modify header information - headers already sent by (output started at /homepages/25/d312846501/htdocs/enviar.php:9) in /homepages/25/d312846501/htdocs/enviar.php on line 33
Y en la linea 33 sale esto
Cita: header('Location: http://www.escuelprocan.es/index.html');