How to add plugins to Ckeditor 4?

I have gone round in circles with this for something that should be very simple that seems to elude me, All I am trying to do is add a few plugins but no buttons show up on the tool bar even though the plugin select box under the Editor appearance showing correctly and are selected.

I have followed the example documentation here http://docs.cksource.com/CKEditor_for_Drupal/Enterprise/Drupal_7/Plugins

In the ckeditor.config.js in the root of the module and I have added my extra plugins to the location modules/ckeditor/plugins

CKEDITOR.editorConfig = function(config) {
  config.extraPlugins = 'widget';
  config.extraPlugins = 'lineutils';

I have ckeditor added in the module folder ckeditor/ckeditor

I understand there is a hook, however it's not very clear if you need to use to create a custom module hook to register each plugin, do I need to make this custom module and register each of these plugins?

Has anyone got these to work? it would be good to know the issues before I spend more time trying to get this to play ball.

Thanks