Hi lucid,
Good question - and glad to hear you're making use of our brand new reviews section.
You can add a review to a section (say, Baby Equipment) by going onto an existing Baby Equipment review and clicking 'Add a new item to our Baby equipment review'. If you'd like to review a product that's already been reviewed, just click 'Add your review and comment' on the product page.
Very well spotted, though, we definitely need a link straight from the category page to add a new review to that section - can't believe that one passed us by!
Thank goodness for the eagle eyes of gransnetters!