I’ve used a lot of Themeforest themes and I can’t find the switch to turn off the entire footer widgets area. I only want the copyright section at the very bottom, not the columnised footer widget area.

How can I turn this whole area off?

That would actually be quite easy to achieve by editing your footer.php template, simply remove or comment out this section in it:

<div class="container">	
	<div class="row">
	  <div class="four columns">
		<?php if ( ! dynamic_sidebar('Footer Widget 1') ) : ?>			
			<h3 class="widgettitle">Footer Widget Area 1</h3>
			<p><a href="<?php echo admin_url('widgets.php'); ?>">Assign a widget to this area now.</a></p>	
		<?php endif; // end widget area ?>	
	  </div>

	  <div class="four columns">
		<?php if ( ! dynamic_sidebar('Footer Widget 2') ) : ?>
			<h3 class="widgettitle">Footer Widget Area 2</h3>
			<p><a href="<?php echo admin_url('widgets.php'); ?>">Assign a widget to this area now.</a></p>					
		<?php endif; // end widget area ?>	
	  </div>

	  <div class="four columns">
		<?php if ( ! dynamic_sidebar('Footer Widget 3') ) : ?>
			<h3 class="widgettitle">Footer Widget Area 3</h3>
			<p><a href="<?php echo admin_url('widgets.php'); ?>">Assign a widget to this area now.</a></p>					
		<?php endif; // end widget area ?>	
	  </div>

	  <div class="four columns">
		<?php if ( ! dynamic_sidebar('Footer Widget 4') ) : ?>
			<h3 class="widgettitle">Footer Widget Area 4</h3>
			<p><a href="<?php echo admin_url('widgets.php'); ?>">Assign a widget to this area now.</a></p>					
		<?php endif; // end widget area ?>		
	  </div> 
	</div> 
	<div class="clear"></div>
</div>