Mod rewrite

[rooftop]

Hi

I have a website with the following url rewrite set

RewriteRule ^Cat-(.*)-(.*).html$ section.php?cat_name=$1&cat=$2

I'd like to change the URLs from

www.mydomain.co.uk/Cat-blah-1.html

to

www.mydomain.co.uk/L1-blah-1.html

I can change the rewrite rule to

RewriteRule ^L1-(.*)-(.*).html$ section.php?cat_name=$1&cat=$2

But is there a way I can redirect any pages listed in search engines so that

www.mydomain.co.uk/Cat-blah-1.html

is redirected

www.mydomain.co.uk/L1-blah-1.html

Thanks