无法通过WordPress插件中的短代码显示自定义帖子元

Question

I've created a plugin that sets up a custom post type ('Programmes'), taxonomy and a short code to display the custom posts. I'm trying to display a custom post meta field (Broadcast Date) via the shortcode. These are the methods I've tried so far:

This is the method I'd have preferred as it allows me to use it for multiple meta values:

if ( $query->have_posts() ) { ?>
    <div class="schedule-container">
        <?php while ( $query->have_posts() ) : $query->the_post();
        $programmeImage = wp_get_attachment_url( get_post_thumbnail_id($post->ID, 'thumbnail') );           
        $programmeMeta = get_post_meta($post->ID,'_meta_content',TRUE);
        ?>
        <div id="programme-<?php the_ID(); ?>" <?php post_class(); ?> style="background-image: url( <?php echo $programmeImage ?> )">
            <div class="schedule-titlebar">
                <h3><a href="<?php the_permalink(); ?>"><?php the_title(); ?></a></h3>
                <p><?php echo $programmeMeta['broadcast-date'] ?></p>
            </div>
        </div>
        <?php endwhile;
        wp_reset_postdata(); ?>
    </ul>
}

But that didn't work so I tried this instead:

if ( $query->have_posts() ) { ?>
    <div class="schedule-container">
        <?php while ( $query->have_posts() ) : $query->the_post();
        $programmeImage = wp_get_attachment_url( get_post_thumbnail_id($post->ID, 'thumbnail') );           
        $programmeBroadcastDate = get_post_meta($post->ID,'broadcast-date',TRUE);
        ?>
        <div id="programme-<?php the_ID(); ?>" <?php post_class(); ?> style="background-image: url( <?php echo $programmeImage ?> )">
            <div class="schedule-titlebar">
                <h3><a href="<?php the_permalink(); ?>"><?php the_title(); ?></a></h3>
                <p><?php echo $programmeBroadcastDate ?></p>
            </div>
        </div>
        <?php endwhile;
        wp_reset_postdata(); ?>
    </ul>
}

and that doesn't work either!

Any ideas? Thanks