New post takes me to 'Index of / wordpress/'

The only changes I have made are adding –
define(‘WP_HOME’,’https://millbrookwoodfuels.co.uk/’);
define(‘WP_SITEURL’,’https://millbrookwoodfuels.co.uk/wordpress/’);
to the wp-config.php under the salts.

This is a server issue – not a WordPress one. Try adding
DirectoryIndex index.php index.html index.htm
to the top of an .htaccess file in your root domain folder.

Thanks Esmi,
Though I was just about to say it’s solved with a work around,
I changed index.php to this:
<?php
/**
* Front to the WordPress application. This file doesn’t do anything, but loads
* wp-blog-header.php which does and tells WordPress to load the theme.
*
* @package WordPress
*/

/**
* Tells WordPress to load the WordPress theme and output it.
*
* @var bool
*/
define(‘WP_USE_THEMES’, true);

/** Loads the WordPress Environment and Template */
require(‘./wordpress/wp-blog-header.php’);

And put it in the public_html folder… someone on Youtube recommended this. Would you say that is ok?

Thanks again!

No – do not ever edit core WordPress files!