echoing menu navigation label other than navigation bar

Hello

Within the dashboard of wordpress, I am in the menu section and have changed the navigation label of a page.

This echos out fine on the front end (navigation bar.) What I want to do is print this elsewhere on the site.

e.g I changed the navigation label to about us. (original page title:Joe bloggs) This echos out to the navigation on the front end as about us (this is fine), However I need to print out the label value (about us) elsewhere on the site e.g. left hand panel sub navigation.

The code I am currently using below:

<?php
  if($post->post_parent)
  $children = wp_list_pages("title_li=&child_of=".$post->post_parent."&echo=0");
  else $children = wp_list_pages("title_li=&child_of=".$post->ID."&echo=0");
  if ($children) {
$parent_title = get_the_title($post->post_parent);?>
<h2 class="lhp_title"><strong><?php echo $parent_title; ?></strong>/h2>
<ul>
<li><a>post_parent)?>"><?php echo $parent_title;?></a><?php echo $children; ?></li>
</ul>
<?php } ?>

[Please post code snippets between backticks or use the code button.]

I want to input the navigation label code instead of the (echo $parent_title;) within h2 tag.

Hope you can help

Thanks