Wordpress - 'Global' settings page for multisite plugin

As a reference

To create network or global settings, you need to do the following

• Add a settings page

  add_submenu_page( 'settings.php'... # cf options.php for blog level`
  

• Add a global option

  add_site_option($key,$value)
  

• Update a global option

  update_site_option($key,$value)
  

• Get a site option

  get_site_option($key)
  

Global settings are saved to the sitemeta table (individual blog settings are saved to <blog_id>_options table

• I think the Settings API functions at the blog level - so uses the options table, not sitemeta. So, you can't use option groups and the like at the network level (please comment if I've got this wrong)