Measurements
To fit chest
41, 46, 51 cm (16, 18, 20 in)
Length from back neck
23, 27, 31 cm (9, 10½, 12 in)
Sleeve seam
13, 17, 20 cm (5, 6½, 8 in)

Each source has a different set of recommended yarns. The following are from the Peter Gregory pamphlet.

Materials
PETER GREGORY DOUBLE KNITTING
Wool Double Knitting (pure new wool)
3, 3, 3 50 gram balls
Super Nylon (machine washable)
5, 5, 6 balls or hanks
Acrylic/Nylon (machine washable)
5, 6, 6 balls
3 buttons
Stitch holders.