Hide Mega Menu sub menu items

Hello,
On my site:

http://brutonknowles.under-development.info/

I have the Mega Menu active and on certain parent menu items have a dropdown that loads various modules etc. On the Sectors & Services dropdown the first thing to be displayed is the sub menu items for that menu. However I have replaced these with visual modules to represent the links. I then deleted the sub menu links. However after a certain time these sub menu items are displayed again.

How can I retain the dropdown functionality but hide the sub menu items?

Thanks

Lee