Sharing Global Menu Links Menu to subsites
So I think I've gone a long way to achieving this.

In the setting.php file of each site I declare a Data Connection called globalmenu that point's to the database belong to the menu's management site.

I make the menu and get the machine name for it; in my case menu-global-menu.

In my page.tpl.php of my theme I have included this

  &lt;?php 
  if ($global_menu){
  print($global_menu);
  }
  ?&gt;


My module

function global_header_preprocess_page(&amp;$variables, $hook) {

 $query_options['target'] = 'globalmenu';   

 $query = db_select('menu_links', 'p', $query_options)
    -&gt;fields('p')
    -&gt;condition('menu_name', 'menu-global-menu', '=')
    -&gt;execute();

 if($query-&gt;rowCount() ==   0) {
    print '&lt;div class="messages error"&gt;&lt;em&gt;No Global Header Configured!&lt;/em&gt;&lt;ul&gt;&lt;li&gt;Check the Global Header Module Help for details&lt;/li&gt;&lt;ul&gt;   &lt;/div&gt;';
}

 $links = array();  
 $markup = "&lt;div class='global-navigation'&gt;&lt;ul class='nav'&gt;";

 foreach ($query as $item) {    
    $markup = $markup ."&lt;li&gt;&lt;a href='".$item-&gt;link_path."' class='global-link'&gt;".$item-&gt;link_title."&lt;/a&gt;&lt;/li&gt;";
 }  

 $markup = $markup ."&lt;/ul&gt;&lt;/div&gt;";  
 $variables['global_menu'] = $markup;
}


There's probably a much better way of doing the markup but I'm a noob so I guess someone will correct me.