As per Tom’s answer somewhere else (sorry!) – this got it working.
add_action( ‘wpsp_after_title’, function( $settings ) {
if ( 321 === $settings[‘list_id’] ) {
$meta = get_post_meta( get_the_ID(), ‘field-name’, true );
if ( $meta ) {
echo $meta;
}
}
} );
Where 321 is the Show Posts list id. I was getting nowhere because I was putting the category ID in. 😀