I threw a duvet in the back of my car, but it was only 1 sheet.
Yeah, just to stop it sliding around and to protect the edges.Sounds like my sort of plan, was it just laid down flat?
The glass is pretty strong and comes with separating packers that are surprisingly good at stopping things moving or flexing.
So long as they are laid flat on a firm base you'll be ok, don't over think it.
I brought 5 back stacked like that with no issues laid on top of each other.
Put the duvet under the first one and wrap it over the rest once stacked.
Neil's place is a bit awkward to find, be prepared to turn sharpish !! ( there is a sign in a tree )