Just knocked up a boonie hat in UCP this evening.
Here are the cut out pieces. I made the hole in the brim too big (the size of the top), so cut out tow additional brim pieces, with a smaller hole. However, I used all four pieces, making for a fairly stiff brim.
The completed hat. It's a bit wobbly and proved to be difficult to put together but not too bad for a first attempt. I won't find out until the morning whether it will actually fit Caroline Bounder. However, I do have three heads to try it on.
I'll post a picture of Caroline wearing the hat later.