Martin Robbins

I’ve created a new WP site in a subfolder and i’ve redirected the domain to look at the subfolder install instead

What is the subfolder name? Exactly how did you accomplish this redirection?

I then created the subdomain ‘oldsite’ to map to the old WP site (in the root folder)

Exactly what did you do to attempt this mapping?

Hello,

I need a free translation plugin for wordpress my site French into English and from English into French because they found that almost no walking or bug.

Thank you in advance.

https://make.wordpress.org/support/handbook/contributing-to-the-wordpress-forums/support-forums-in-your-language/

You are welcome.

So your site appears OK at http://lincsmulticlean.co.uk/ … And the login screen seems OK at http://lincsmulticlean.co.uk/wp-admin/ … Can you login there?

I’ve mapped ‘oldsite’ subdomain to root directory of my 1and1 webserver so that my old site is still accesible.

Can you tell us more about your old site? Is it an html site in the same folder as your WordPress? Are you attempting to make visible both sites?

Another possibility is use custom fields for whatever she fills in. And write a template to output the custom fields, and all the html and shortcodes instead of putting it in the content editor. This kind of functionality can be implemented easily enough with the plugin Advanced Custom Fields.

If you have theme options panels in wp-admin, best to go with that. If you want to edit functions.php yourself, best to create a child theme and edit the child functions.php and not the parent.

Instead of editing the core code, one solution is to filter in your new code via action hook:
https://codex.wordpress.org/Plugin_API/Action_Reference

Another option, have additional stylesheet in your theme and properly enqueue it. There’s plenty plugins and tutorials out there that do it for the wp-admin pages. I do admin css like this:

<?php
/**
 * Plugin Name: WP Admin CSS

 * Description:
 * Version:
 */

      //First solution : one file
      add_action( 'admin_enqueue_scripts', 'load_admin_style' );
      function load_admin_style() {
//        wp_register_style( 'admin_css', get_template_directory_uri() . '/admin-style.css', false, '1.0.0' );
//OR
        wp_enqueue_style( 'admin_css', get_stylesheet_directory_uri() . '/admin-style.css', false, '1.0.0' );
       }
/*
      //Second solution : two or more files.
      add_action( 'admin_enqueue_scripts', 'load_admin_styles' );
      function load_admin_styles() {
        wp_enqueue_style( 'admin_css_foo', get_template_directory_uri() . '/admin-style-foo.css', false, '1.0.0' );
        wp_enqueue_style( 'admin_css_bar', get_template_directory_uri() . '/admin-style-bar.css', false, '1.0.0' );
      }
*/
 ?>

For what it’s worth here is article re staging via git or bitbucket:
http://www.wpbeginner.com/wp-tutorials/how-to-create-staging-environment-for-a-wordpress-site/

Most likely you have deleted the /wp/index.php

Get a copy from a backup or download a fresh wordpress.zip file and use the file /wordpress/index.php from the zip.