title: Faking Post Request with PHP Curl - Rejection
body: <p>I am trying to build a script that posts information into the <a href="http://track2.royalmail.com/portal/rm/track" rel="nofollow">RoyalMail tracking system</a> and extracts the output.</p>
  
  <p>What I currently have is getting an error from their server - see the link, somehow it is detecting that I am not using their website as per normal and throwing me an error.</p>
  
  <p>Things I think I have taken into account:</p>
  
  <ul>
  <li>Using an exact copy of their form by parsing it beforehand (the post parameters)</li>
  <li>Saving the cookies between each request</li>
  <li>Accepting redirect headers</li>
  <li>Providing a refer header that is actually valid (the previously visited page)</li>
  </ul>
  
  <p>Does anyone know anything else I need to check or can figure out what I am doing wrong?</p>
  
  <p>A full copy of the source is at EDIT: please see my answer below</p>