Many thanks Charles, that's worked a dream - cheers.
One last thing, to redirect a user from a particular IP address to another page on the same website, I'm trying :
RewriteEngine on
RewriteCond %{REMOTE_ADDR} ^92\.53\.62\.24$ [OR]
RewriteCond %{REMOTE_ADDR} ^24\.151\.467\.151$
RewriteRule ^(.*)$ http://www.websitename.com/folder/index.php [L]