The stitching was all done by machine apart from a few tiny hand stitches. I used Superior Threads invisible thread ( with fine cotton in the bobbin) and an adjusted blind hem stitch on my machine. I found loosening the top tension made sewing with this thread much smoother.
Jenny Rayment has written several books on folding and pleating and I'm told she's a very entertaining speaker and runs excellent workshops. She also has an online subscription site with lots of videos to watch called Just Hands On TV.