Hello Dotty,
You can use following code snippet to get gd_place submit action.
/**
 * Fires once a post has been saved.
 *
 * @param int     $post_ID Post ID.
 * @param WP_Post $post    Post object.
 * @param bool    $update  Whether this is an existing post being updated or not.
 */
function geodirectory_submit_gd_place( $post_ID, $post, $update = false ) {    
    if (  !empty( $post->post_author ) && !( defined( 'DOING_AUTOSAVE' ) && DOING_AUTOSAVE ) ) {
        $user_id = $post->post_author;
        update_user_meta( $user_id, '_new_user', '0' );
        error_log( 'geodirectory_submit_gd_place() -> user_id : ' . $user_id . ', post_ID : ' . $post_ID );
    }
}
add_action( 'save_post_gd_place', 'geodirectory_submit_gd_place', 10, 3 );
p.s. feel free to share your valuable feedback with a nice review here anytime : https://wordpress.org/support/view/plugin-reviews/geodirectory
It really helps us grow more. 🙂
Thanks,
Kiran