echo the_modified_date('j/M/Y') in after_title

Hi,

I want to add a “last updated date” in a span inside a specific widget
here’s my function so far

function add_front_sidebar(){
	register_sidebar( array(
		'name' => 'Front Sidebar',
		'id' => 'front-sidebar',
		'before_widget' => '<div id="%1$s" class="widget-container %2$s">',
		'after_widget' => '</div>',
		'before_title' => '<h3 class="widget-title">',
		'after_title' => '<span class="last-update">Last Updated: ' .  the_modified_date('j/M/Y') . '</span></h3>'
	) );
} add_action('widgets_init', 'add_front_sidebar');

I have two issues:
1. I can’t get the_modified_date to echo out
2. Is there away to target the corrected <span class="last-update">Last Updated: ' . the_modified_date('j/M/Y') . '</span> to only appear in a certain widget, in this case the widget title is What’s New

Thanks