3rd attempt.

It's taken three attempts to join the side panels correctly.  First time, some of my hand stitching of the back showed on the front.  Second time, I'd calculated wrongly - I'd multiplied 13½ by 3 and made 39½ - oops.

Finally, I got it right, and then fastened the three side panels to the centre panel.  Now I know what I'm doing, the second side should be simple!!

It's been a lovely day.  S and T popped round for morning coffee, and admired our garden, including our use of the gate we acquired from them.  It was so great to be able to sit outside to enjoy our coffees.