From the book:
“Garter stitch with a small wave in the middle - simple but effective. A crochet edge can be workes along the centre for buttonholes.”

Finished chest measurements: 47, 52, 56, 61, 65cm.
Finished sleeve seam: 11.5, 14.5, 17, 20, 22.5cm

2(2:3:3:4) balls Rowan Cashsoft DK
5x12mm buttons for all sizes.