How do I rename a CCK content type

I've created a CCK content type which I've populated with lots and lots of data - called 'my showroom product'

Now I'm trying to style up the page I find that the title "content-my_showroom_product.tpl.php" is too long to save due to the number of characters. I've tried exporting the database and renaming every instance I can find of 'my showroom product' to "myproduct" so the node content is delivered by 'content-myproduct.tpl.php' but it just won't work.

Has anyone any clues on how to do this.

Just renaming it in the admin section doesn't rename the original database tables - just the human readable form.

thanks

Ian