Thanks but removing
Code:
<div id="single-home-container"></div>
from test.php doesn't seem to make a difference.
Header.php
Code:
<script>
$(document).ready(function(){      
	$.ajaxSetup({cache:false});     
	$(".locationID").click(function(){         
		var post_id = $(this).attr("rel"); 
		//alert($(this).attr('rel'));
		$("#single-home-container").html("loading...");         
		$("#single-home-container").html(post_id);
		
		$("#single-home-container").load("test.php", { 'locationID': $(this).attr("rel") } );
		
		//$.post("test.php", {"locationID": post_id}, function (txt) {
		//	alert(txt);
		//});

		return false;    
	});  
}); 
</script>
footer.php has the loop tp produce the links:
Code:
			<?php	
			$args = array( 
						  'post_type' => 'locations', 
						  'order'    => 'DESC'
						  );
			$loop = new WP_Query( $args );
			while ( $loop->have_posts() ) : $loop->the_post();
			?>	
				<li><a href="#" rel="<?php the_ID(); ?>" class="locationID"><?php the_title(); ?></a></li>
			<?php	
			endwhile;	
			wp_reset_query();
			?>
Also is the include to test.php
Code:
<?php include(TEMPLATEPATH."/test.php"); ?>
Test.php has this to check the value
Code:
<?php 
$the_location_id1 = $_GET['locationID'];
echo '<br>Loc ID '. $the_location_id1;
?>
And the main query I wish to pass the value to:
Code:
			<?php	
			$args = array( 
						  'post_type' => 'locations', 
						  'posts_per_page' => 1,
						  'p' => $the_location_id1 ,
						  );
			$loop = new WP_Query( $args );
			while ( $loop->have_posts() ) : $loop->the_post();
			?>	
			<?php the_title(); ?>
			<?php	
			endwhile;	
			wp_reset_query();
			?>
Which i believe is the right set up from what's been posted so far!?
Thanks again, it really is appreciated