Download content of CSV file via curl from secure POST request - php

Question

I'm trying to download a file that is generated when a POST button is pressed on an HTTPS page. I'm having to pass the contents of a cookie to show that I'm logged in but I've tested that elsewhere on the same site and that's all working fine.
I'm successfully generating the POST request to request the data that I need and I'm sending it but I'm getting nothing back from the web server at all.
Here's my code:
// Build header
$header = array();
$header[0] = "Accept: text/xml,application/xml,application/xhtml+xml,";
$header[0] .= "text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5";
$header[] = "Cache-Control: max-age=0";
$header[] = "Connection: keep-alive";
$header[] = "Keep-Alive: 300";
$header[] = "Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7";
$header[] = "Accept-Language: en-us,en;q=0.5";
$header[] = "Pragma: ";
$header[] = "Content-Type: application/x-www-form-urlencoded";
// Now do transfer
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, "https://domain/pathtoscript");
// Send referer to make this look real
curl_setopt($ch, CURLOPT_REFERER, $referer);
// And disguise ourselves as a browser
curl_setopt($ch, CURLOPT_USERAGENT, $agent);
// Return results as a string
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
// Follow redirects
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, FALSE);
curl_setopt($ch, CURLOPT_VERBOSE, 1);
// Now send post data
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS, $postData);
// Define where we can store cookies
curl_setopt($ch, CURLOPT_COOKIEFILE, $cookieFile);
curl_setopt($ch, CURLOPT_COOKIEJAR, $cookieFile);
// Sender header and permitted encodings
curl_setopt($ch, CURLOPT_HTTPHEADER, $header);
curl_setopt($ch, CURLOPT_ENCODING, '');
// Actually do it !
$result = curl_exec ($ch);
curl_close ($ch);
// Show result in browser (should be CSV text file)
echo $result;
What am I doing wrong ? I don't want a dialogue box to open to prompt me to save the file, I'd just like the content of the file in $result so that I can parse it later in my application.
Thanks in advance !