perch_pages_navigation - Ordering the pages

I have a NavGroup called 'location'. This is to appear as a list of link on a map page. My different town location pages will be automatically added to this navgroup.

However I cant seem to set the order of these pages? Currently they just seem to fall in a random order and not in the same order I set in the Perch pages view.

Please help.

This is my code:

<?php 
      perch_pages_navigation(array(
      'template' => 'location-nav.html',
      'include-parent' => true,
      'navgroup' => 'location'
      ));
?>