After much searching myselft, I found the answer to this here:
To summarise, the code to append a '>' to the end of each category is:
<?php
$taxonomy = 'category taxonomy';
$orderby = 'name';
$show_count = 1; // 1 for yes, 0 for no
$pad_counts = 0; // 1 for yes, 0 for no
$hierarchical = 1; // 1 for yes, 0 for no
$title = '';
$empty = 0;
$args = array(
'taxonomy' => $taxonomy,
'orderby' => $orderby,
'show_count' => $show_count,
'pad_counts' => $pad_counts,
'hierarchical' => $hierarchical,
'title_li' => $title,
'hide_empty' => $empty
);
?>
<ul>
<?php
$variable = wp_list_categories($args);
$variable = str_replace('</a>', ' ></a>', $variable);
echo $variable;
?>
</ul>
Hope this helps. The key is the $empty parameter.