Customise Custom Error Pages WordPress plugin

/*
 * Plugin Name:       Custom Error Pages Child Plugin
 * Plugin URI:        https://www.wordpressdeveloperlondon.com/custom-error-pages-child/
 * Description:       Custom Custom Error Pages plugin code dependant on Custom Error Pages plugin
 * Version:           1.0.1
 * Requires at least: 5.2
 * Requires PHP:      7.2
 * Author:            wordpressdeveloperlondon
 * Author URI:        https://www.wordpressdeveloperlondon.com
 * License:           GPLv3
 * License URI:       https://www.gnu.org/licenses/gpl-3.0.txt
 * Text Domain:       custom-error-pages-child
 * Domain Path:       /languages
 * Requires Plugins:  custom-error-pages
 */

/*
 * -----------------------------------------------------------------------------------------------------
 * WordPress plugin ID: 8946 custom-error-pages-child version 1.0.1
 * WordPress plugin dependancy: Custom Error Pages
 * -----------------------------------------------------------------------------------------------------
 */

if((get_option("wordpressdeveloperlondon_settingwordpress_seo_8946")) != 1) 
{
	function wordpressdeveloperlondon_files_wordpress_seo_8946()
	{
		$plugin_url = plugin_dir_url(__FILE__);

		wp_enqueue_style("wordpress_seo_8946-stylesheet", $plugin_url . "css/style.css");
		wp_enqueue_script("wordpress_seo_8946-script", $plugin_url . "js/scripts.js", array("jquery"), "1.0.0", true);
	}
	add_action("wp_enqueue_scripts", "wordpressdeveloperlondon_files_wordpress_seo_8946", 80);
}

if(get_option("wordpressdeveloperlondon_setting_htmlwordpress_seo_8946") != 1)
{
	function plugin_sourcewordpress_seo_8946()
	{