Works Perfectly!

Thank you, thank you, thank you – this is a life saver. And BTW to add excerpts to a custom post use this:

add_action('init', 'my_custom_init');
function my_custom_init() {
	add_post_type_support( 'NAME_OF_CUSTOM_POST', 'excerpt' );
}

Once you have done that the custom post name appears in the settings for this plugin and you can check the box to enable it.

Brilliant!