Coupon code in admin order email

I think i’ve found a quick way of adding it in myself:

add_action( 'jigoshop_after_email_order_info', 'add_coupon_code_email', 10000, 1 );
function add_coupon_code_email( $orderId ) {
	$orderData = get_post_meta( $orderId, 'order_data', true );
	$discounts = @$orderData->order_discount_coupons;
	$codes = "";
	foreach($discounts  as $discount){
		$codes .= @$discount->code . ", ";
	}
	echo "Discount Code Used: $codes". PHP_EOL. PHP_EOL;
}

The @ are to prevent errors showing up for the moment as the site is live. Not ideal I know but the client wants the information in the order email as they don’t want to log into the admin to check on the order!

So, is my code correct? It doesn’t look like it is working and as this is a live site I can’t debug it as well as I’d like.

The main thing I want to check is that the parameter $orderId will be passed through using the hook as I think it is.

Thanks.