Brenda, that's been the problem. I just can't get round those small notches neatly. It looks a mess. The Sailrite video I watched said it was acceptable to ignore the notches if they were very small, and I've now re-done the back, covering the notches with patches where the fabric has weakened.
With hindsight, I could have used it as a design opportunity, and it certainly doesn't look as pretty as I would like, but heck, it's a story chair.....
Looking at it, I could have done much better, but, it's done now. The seat cushion is on the machine, ready for me to cover the notches.
Jessie