Using get_page_uri should do the trick:
<h2><a href="' . get_page_uri($pageChild) .'">' . $pageChild->post_title . get_the_post_thumbnail($pageChild->ID).'</a></h2>
Using get_page_uri should do the trick:
<h2><a href="' . get_page_uri($pageChild) .'">' . $pageChild->post_title . get_the_post_thumbnail($pageChild->ID).'</a></h2>