I (...) have fixed the issue in IE using conditional formating
That is correct for IE8, but not for IE7 and 9. Open the site in IE9, press F12 and play with the browser mode to see for yourself. Also, in IE6 there is no navmenu, and the content is way too far down.
Sorry that I have such bad news for you.
How to: Target IE in, Position in, Center in, Create a Fixed ('Sticky') Footer with, and Create a Drop-Down/Fly-Out Menu with CSS: Website Laten Maken Amsterdam