htaccess rewrite to new domain

I have this:

Options -Indexes
RewriteEngine On
RewriteCond %{HTTP_HOST} ^findmyfiver\.com$ 
RewriteRule (.*) http://www.findmyfiver.com/$1 [L,R]

Which successfully forces a user to the www. version on the site; however I want to redirect a user to a specific domain and page when they enter:

findmyfiver.com/tester.php to findmyfiver.co.uk/tester.php

How is this done?

Options -Indexes
RewriteEngine On
RewriteCond %{HTTP_HOST} ^findmyfiver\.com$ 
# Add a rule to rewrite tester.php to a different domain
# Before your other catch-all rule
RewriteRule ^tester\.php http://findmyfiver.co.uk/tester.php [L,R=301,QSA]
RewriteRule (.*) http://www.findmyfiver.com/$1 [L,R]