Hi Tim,
Viewing source seems to show the correct value (the oldest referrer) in the hidden field.
It may be your form tag:
<form method="POST" action="" class="form-horizontal" role="form"/>
Because it has an action of "" it will submit to the current url, which may be ?referrer=whatever and then when PHP runs it may combine the ?referrer from the URL and the hidden field and give priority to the one in the URL.
Can you try changing your form action to ? as in:
<form method="POST" action="?" class="form-horizontal" role="form"/>
Let me know if that works for you.
Dave Edis - Senior Developer
interactivetools.com