step 1 htaccess

# BEGIN WordPress

RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ – [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]

RewriteEngine On
RewriteCond %{SERVER_PORT} 80
RewriteRule ^(.*)$ https://www.websitedomainname.co.uk/$1 [R,L]

# END WordPress

step 2 settings general add s https
WordPress Address (URL)https://www.websitedomainname.co.uk
Site Address (URL) https://www.websitedomainname.co.uk
step 3 install Better Search Replace

Note the http in the top
https in the bottom
select and hightlight all tables
REMOVE tick from Run as dry run
RUN SEARCH AND REPLACE