Right had some sleep.
No, when you add the include() statement it only shows the included part, so I've found anyway. BUT when the site is tried on a http server it works perfectly. If you haven't got a testing server on your system try xampp, easy to setup and use.
Ok, if you use something like this:-
$meta = $metadescription['DESCRIPTION'];
echo "<a href =\"metatags.php?title=$title&meta=$meta\">Link here</a>";
This should pass the values of $title and $metadescription['DESCRIPTION'] to metatags.php
On metatags.php you can access the variables by using this:-
$title = $HTTP_GET_VARS['title'];
$metadescription = $HTTP_GET_VARS['meta'];
you could assign a default value to $title by using something like this:-
if($title == NULL){$title = "default title here";}
I'm not 100% certain on how to use the values in the meta sections on the headers but I have tried to help you as much as I can my friend.