Change menu displayed with menu toggle

Hi Guys,

I’ve been searching for an answer to this but have had no luck and Im hoping someone can help.

I currently have 3 menus for my site, lets call them A, B and C for ease. Menus A and B show up on the normal desktop version of the site, while menu C (a combination of both menus A and B) is not used.

Then when the screen is reduced for mobiles and tablets etc I hide menus A and B using media queries and use menu toggle to display a mobile friendly menu.

The problem however is that I want the menu that is displayed using menu toggle to be menu C but at present it is defaulting to menu A.

The code I am using is as follows:

<nav id="site-navigation" class="navigation main-navigation" role="navigation">
    	<a class="screen-reader-text skip-link" href="#content" title="<?php esc_attr_e( 'Skip to content', 'twentythirteen' ); ?>"><?php _e( 'Skip to content', 'twentythirteen' ); ?></a>
    	<?php wp_nav_menu( array( 'theme_location' => 'primary', 'menu_class' => 'nav-menu' ) ); ?>
        <h3 class="menu-toggle"><?php _e( 'Menu', 'twentythirteen' ); ?></h3>
    </nav>

I’ve tried the following:

<h3 class="menu-toggle"><?php wp_nav_menu( array( 'theme_location' => 'small-screen-nav-menu', 'menu_class' => 'nav-menu' ) ); _e('Menu'); ?> </h3>

and this shows up menu C (which is the small-screen-nav-menu in reality) but before menu C it still shows menu A!?

How can I get rid of menu A and just use menu C (small-screen-nav-menu)?

I am using a child theme of twentythirteen and have defined the theme name as: Ecoexplore in the style.css file and the text domain as: ecoexplore but changing

<h3 class="menu-toggle"><?php _e( 'Menu', 'twentythirteen' ); ?></h3>

to

<h3 class="menu-toggle"><?php _e( 'Menu', 'ecoexplore' ); ?></h3>

or

<h3 class="menu-toggle"><?php _e( 'Menu', 'Ecoexplore' ); ?></h3>

Doesn’t seem to work.

Any help would be much appreciated!