I am having double glazing installed this week. They started upstairs with regular glass and are completing downstairs tomorrow. All the sealed units have been left with me overnight. I specified laminated glass downstairs and the units are marked as 6.8mm laminated /4mm toughened. How can I tell which side is the laminated side? I just want to make sure that they install them the right way around tomorrow (laminated on the outside). Many thanks.