Customizing Custom Related Posts title

We don’t have a setting for that at the moment, but you can achieve that by adding the following code to your theme’s functions.php file:

function crp_output_list_title( $title ) {
	$title = str_replace( '<h3', '<h2', $title );
	$title = str_replace( '</h3>', '</h2>', $title );

	return $title;
}
add_filter( 'crp_output_list_title', 'crp_output_list_title' );

Thank you so much for your helpful reply. I’m amazed at such service on a Sunday evening! I’ve just copied and pasted the code you sent me into my theme’s functions.php file as you suggested. Problem solved.