You will need 4(4,4, 5, 5, 5) buttons. Sirdar used their buttons # B5611-0058.

Finished measurements:
Jacket
Chest circumference: 18(19.5, 21.25, 21.75, 22.5, 24)“ 46(48, 54, 55, 57, 61) cm
Finished length: 9.75(10.75, 11.75, 12.5, 13.5, 14)” 25(27, 30, 32, 34, 36) cm
Sleeve length to armhole: 6.25(6.5, 7, 8, 8.75, 9.75)“ 16(17, 18, 20, 22, 25) cm

Leggings
Hip Circumference : 19(20.5, 21.25, 22, 22.75, 23.75)“ 48(52, 54, 56, 58 ,60) cm
Finished length: 18(19.25, 21.25, 23.25, 24.75, 26.5)” 46(50, 54, 59, 63, 67) cm
Inseam: 7(8, 8.75, 9.75, 10.75, 11.75)“ 18(20, 22, 25, 27, 30) cm

Yarn used:
Sirdar Snuggly DK
Jacket
A. 505 Ketchup - 2(3, 3, 3, 3, 4) balls
B. 251 White - 1 ball for all sizes
C. 200 Milky - 1 ball for all sizes

Leggings/ Dungarees
A. 505 Ketchup - 2(2, 2, 3, 3, 3) balls
B. 251 White - 1 ball for all sizes
C. 500 Sunshine - Oddment