Jon,
You need to specify the name of the sender. Let $name hold that, and change your code to:
mail("np50@dial.pipex.com","Access World - Repair:" . $country,$body,"From: " . $name . " <".$Email.">\r\nContent-Type: text/html");
That should work, but I've never changed the Content-Type in an email, so I don't know if that part is correct. If the above doesn't work, try:
mail("np50@dial.pipex.com","Access World - Repair:" . $country,$body,"From: " . $name . " <".$Email.">");