I changed servers, now none of my original mail scripts work. Strange.
Anyway I have been looking around for some alternative scripts and stumbled up on this.
I have tested the script below and it sends fine to, two people.
If I add anymore email address in the $to, it no longer works.
I know this script is not ideal, but it does the job I need it to do.
<?php
$to = "$email_address1,$email_address2";
$subject = "Test mail";
$message = "This is a test?";
$from = "$email_address";
$headers = "From: $from";
mail($to,$subject,$message,$headers);
echo "Mail Sent.";
?>