HTACCESS redirection

Hi all,

We are using wordpress multisite for a website.
We have some url that we need to redirect to new one.
We have tried few htaccess redirection but nothing work.

The last line is the redirection that we cannot make works.

RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]

#redirect mobile browsers
RewriteCond %{HTTP_USER_AGENT} ^.*iPhone.*$
RewriteRule ^(.*)$ https://www.ourdomain.co.uk/blog [R=301,L]
RewriteCond %{HTTP_USER_AGENT} ^.*BlackBerry.*$
RewriteRule ^(.*)$ https://www.ourdomain.co.uk/blog [R=301,L]
RewriteCond %{HTTP_USER_AGENT} ^.*Palm.*$
RewriteRule ^(.*)$ https://www.ourdomain.co.uk/blog [R=301,L]

RewriteCond %{HTTP_HOST} ^ourdomain.co.uk$
RewriteRule ^(.*) https://www.ourdomain.co.uk/$1 [QSA,L,R=301]

# uploaded files
RewriteRule ^([_0-9a-zA-Z-]+/)?files/(.+) wp-includes/ms-files.php?file=$2 [L]

# add a trailing slash to /wp-admin
RewriteRule ^([_0-9a-zA-Z-]+/)?wp-admin$ $1wp-admin/ [R=301,L]

RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule ^ - [L]
RewriteRule  ^([_0-9a-zA-Z-]+/)?(wp-(content|admin|includes).*) $2 [L]
RewriteRule  ^([_0-9a-zA-Z-]+/)?(.*\.php)$ $2 [L]
RewriteRule . index.php [L]

RewriteCond %{QUERY_STRING} page=135
RewriteRule ^index\.php$ https://www.ourdomain.co.uk/about-us/$1? [R=301,L]

Do you have any ideas?

Thanks