GridMarket Theme Options

Hi, I am trying to get GridMarket Theme Options to stop displaying in the admin menu for sub sites. I tried admin menu editor (changing roles, deleting the menu item, hiding the menu item) but it seem that GridMarket overrides that plugin.
How do I prevent that one line from showing in the menu so that sub sites don't fiddle with the settings? This way they can still edit the header and background menu items.

Thx