Category Name to Show

Hi All,
Since updating my wordpress from 2.9 to 3.1 (The theme doesn’t like WP version upgrades so we go nice and slowly ;).

We’ve had a Category name which WAS showing, but now, is not.
The code concerned is this:

// enter the IDs of which categories you want to display
$display_categories = array(6);
foreach ($display_categories as $category) { ?>
    <div class="clearfloat">
      <?php query_posts("showposts=4&cat=$category");
	    $wp_query->is_category = false;
		$wp_query->is_archive = false;
		$wp_query->is_home = true;
		 ?>
      <h3><a>">
        <?php
	// name of each category gets printed
	 // single_cat_title(); ?>
        </a></h3>
      <?php while (have_posts()) : the_post(); ?>
      <?php

Category ‘^’ posts and title names are showing but the category title, above the posts, is not.

I’m not sure if the answer is posted here: http://wordpress.org/support/topic/single_cat_title?replies=3

So can anyone help out with some code I need to replace please.

Many Thanks.