You will need six buttons.

Finished measurements:
Chest circumference: 18( 19.75, 20.5, 21.25, 21.75, 22.5)“ 46( 50, 52, 54, 55, 57) cm
Finished length: 10.25( 11, 12, 12.5, 13.75, 14.5)” 26( 28, 31, 32, 35, 37) cm
Sleeve length: 6 (6.25, 6.5, 7.5, 8.25, 9.5)“ 15( 16, 17, 19, 21, 24) cm

Yarn used:
Sirdar Snuggly DK
A. 446 Rice Pud - 1( 2,2,2,2,2) balls
B. 326 Denim Blue - 1 ball for all sizes
C. 513 Tawny - 1 ball for all sizes