For anyone looking for this same solution I figured it out (apart from adding a different class to parents and children, unfortunately this puts the parent in the same nest as its children but with css and query ill be able to differentiate these.
Here is the code;
<?php
global $authordata, $post;
$authors_posts = get_posts( array(
'author' => $authordata->ID,
'post_parent' => 0,
'orderby' => 'menu_order',
'post_type' => 'page',
'posts_per_page' => 5 ) );
foreach ($authors_posts as $post) {
?>
<ul> poo
<li>
<?php
echo '<a href="' . get_permalink( $post->ID ) . '">' . $post- >post_title . '</a>';
?>
</li>
<?php
wp_list_pages('title_li=&depth=0&child_of=".$post->ID."');
?>
</ul>
<?php
}
?>