boswall_checkout_clearer.php

<?php
/*
Plugin Name: Boswall's Checkout Clearer
Plugin URI:  #
Description: Fixing the checkout privacy error in Loushou: ACF to WooCommerce plugin. http://wordpress.org/support/topic/previous-form-entry-visible-on-next-form-view/
Version:     1
Author:      Boswall
Author URI:  https://glaikit.co.uk/
*/

defined( 'ABSPATH' ) or die( 'No script kiddies please!' );

function boswall_checkout_clearer_menu_option() {
    add_management_page(
        'Boswall\'s Checkout Clearer',
        'Boswall\'s Checkout Clearer',
        'manage_options',
        'boswall_checkout_clearer',
        'boswall_checkout_clearer_page'
    );
}
add_action( 'admin_menu', 'boswall_checkout_clearer_menu_option' );

function boswall_checkout_clearer_page() {
  global $wpdb;

  ?>
  <div class="wrap">
    <h2>Boswall's Checkout Clearer</h2>
  <?php

  if ($_POST['action'] === 'delete') {
    $wpdb->query( "DELETE FROM {$wpdb->options} WHERE option_name LIKE '%checkout_0_%'" );
    ?>
    <div class="notice notice-success is-dismissible">
        <p>All default checkout data removed</p>
    </div>
    <?php
  }

  $results = $wpdb->get_results( "SELECT * FROM $wpdb->options WHERE option_name LIKE '%checkout_0_%'" );
  if ( ! $results ) {
    echo '<p>No default checkout data found</p>';
  } else {
    echo '<p>Default checkout data found</p><ul>';
    foreach ($results as $result) {
      echo '<li><strong>'.$result->option_name.':</strong> '.$result->option_value.'</li>';
    }
    echo '</ul>';
    ?>
    <!-- <code><?php print_r($results); ?></code> -->
    <form class="" method="post">
      <input type="hidden" name="action" value="delete">
      <input type="submit" id="dodelete" class="button button-primary action" value="Delete all">
    </form>
    <?php
  }

  echo '</div>';

}