Perfect, but I have another question - I have used sort=menu_order and orderby=ASC which works find, unless I use the cftsearch.
Picking through the code I found that if I changed $_REQUEST['order'] = DESC to ASC in this part of your plugin:
function custom_field_template_posts_orderby($sql) {
global $wpdb;
if ( empty($_REQUEST['order']) || ((strtoupper($_REQUEST['order']) != 'ASC') && (strtoupper($_REQUEST['order']) != 'DESC')) )
$_REQUEST['order'] = 'DESC';
Then I get ASC order, so what do I need to do to NOT change your code, but satisfy the conditional statement so I get the ASC order I want?