Add England, Wales, Scotland, and Northern Ireland to WooCommerce shipping zones

rs-uk-szones.php

add_filter( 'woocommerce_countries',  'rs_add_my_country' );
function rs_add_my_country( $countries ) {
  $new_countries = array(
			'NIRE'  => __( 'Northern Ireland', 'woocommerce' ),
			'SCO'  => __( 'Scotland', 'woocommerce' ),
			'WAL'  => __( 'Wales', 'woocommerce' ),
			'ENG'  => __( 'England', 'woocommerce' ),
	                    );

	return array_merge( $countries, $new_countries );
}

add_filter( 'woocommerce_continents', 'rs_add_my_country_to_continents' );
function rs_add_my_country_to_continents( $continents ) {
	$continents['EU']['countries'][] = 'NIRE';
	$continents['EU']['countries'][] = 'SCO';
	$continents['EU']['countries'][] = 'WAL';
	$continents['EU']['countries'][] = 'ENG';
	return $continents;
}