Sorry not sure what you mean by success page? I have the form redirect to a thank you page if that's what you mean? the thank you page is in html.
Also I tried applying the code to the page with the form on and it showed a load of code when loading the page. ive taken the line of code you gave me off now.
here's the page by the way.
http://www.stagnhendotshirts.com/contact.php