Ok, try manually resetting your plugins (no Dashboard access required). If that resolves the issue, reactivate each one individually until you find the cause.
If that does not resolve the issue, access your server via SFTP or FTP, or a file manager in your hosting account’s control panel (consult your hosting provider’s documentation for specifics on these), navigate to /wp-content/themes/ and rename the directory of your currently active theme. Hopefully, this will force the default theme to activate and rule out a theme-specific issue (theme functions can interfere like plugins).
And, if that doesn’t work, visit the steps at https://developer.www.ads-software.com/advanced-administration/upgrade/migrating/#changing-the-site-url under “Changing the URL directly in the database” and make sure that the siteurl and home values are both set to https://www.fhithich.uk
(you’ll find phpMyAdmin in your hosting account’s control panel).
Finally, if those values are already correct, try downloading WordPress again, access your server via SFTP or FTP, or a file manager in your hosting account’s control panel (consult your hosting provider’s documentation for specifics on these), and delete then replace your copies of everything on the server except the wp-config.php file and the /wp-content/ directory with fresh copies from the download. This will effectively replace all of your core files without damaging your content and settings.
If you’d like to manually make a backup of your site first, please follow the steps at https://www.ads-software.com/documentation/article/wordpress-backups/
Some uploaders tend to be unreliable when overwriting files, so don’t forget to delete the original files before replacing them.