Bar separated navigation by extending Walker_Page

This question follows on from this one:

Bar separated navigation by extending Walker_Nav_Menu

I’m trying to do the same thing but this time I’m extending Walker_Page instead.

The issue I’m having is that I’m setting the depth to 1 and in that depth there might be 4 pages. But in the walk() the number of elements returned are more. Because the number of elements returned are more than the amount of pages being showed then I get one bar | too many added to the end of my menu.

Here is the code I have so far:

<?php
$children = get_pages('child_of='.$post->ID);
if( 0 != count( $children ) ) {
    $child_of = $post->ID;
} else {
    $child_of = $post->post_parent;
}
$args = array(
    'depth'        => 1,
    'child_of'     => $child_of,
    'title_li'     => '',
    'echo'         => 1,
    'sort_column'  => 'menu_order, post_title',
    'walker' => new Bar_List_Walker_Page
);
wp_list_pages( $args );
?>

My Walker:

class Bar_List_Walker_Page extends Walker_Page {
    public $count;
    public $running_count;
    function __construct() {
        $this->count = 0;
        $this->running_count = 0;
    }
    function start_el(&$output, $page, $depth, $args, $current_page) {
        extract($args, EXTR_SKIP);
        $css_class = array();
        if ( !empty($current_page) ) {
            $_current_page = get_page( $current_page );
            _get_post_ancestors($_current_page);
            if ( isset($_current_page->ancestors) && in_array($page->ID, (array) $_current_page->ancestors) )
                $css_class[] = 'current_page_ancestor';
            if ( $page->ID == $current_page )
                $css_class[] = 'current_page_item';
            elseif ( $_current_page && $page->ID == $_current_page->post_parent )
                $css_class[] = 'current_page_parent';
        } elseif ( $page->ID == get_option('page_for_posts') ) {
            $css_class[] = 'current_page_parent';
        }
        $css_class = implode(' ', apply_filters('page_css_class', $css_class, $page));
        $output .= '<a class="' . $css_class . '" href="' . get_permalink($page->ID) . '">' . apply_filters( 'the_title', $page->post_title, $page->ID ) . '</a>';
    }
    function end_el(&$output, $item, $depth) {
        $this->running_count++;
        if($this->count > $this->running_count)
            $output .= " | ";
    }
    function walk( $elements, $max_depth, $r ) {
        $this->count = count($elements);
        return parent::walk( $elements, $max_depth, $r );
    }
}

How do I get my walker to get the correct amount of pages in the level I’m targeting?