Press pieces carefully, following any yarn care instructions on the ball band. Join both shoulder seams using back stitch, or mattress stitch if preferred.
With RS facing, using 3.25mm needles and yarn D, knit across 12 sts on right front holder, pick up and knit 22 ( 22: 24: 24: 26) sts up right side of front neck, and 5 sts down right side of back neck, knit across 39 ( 39: 41: 41: 43) sts on back holder dec ( dec: inc: inc: dec) 1 st at centre, pick up and knit 5 sts up left side of back neck, and 22 ( 22: 24: 24: 26) sts down left side of front neck, then knit across 12 sts on left front holder. 116 ( 116: 124: 124: 128) sts. Row 1 (WS): K1, P2, *K2, P2; rep from * to last st, K1. Row 2: K3, *P2, K2; rep from * to last st, K1. These 2 rows form rib. Cont in rib for a further 5 rows, ending with RS facing for next row. Cast off in rib.
With RS facing, using 3.25mm needles and yarn D, pick up and knit 124 ( 128: 132: 136: 140) sts evenly down entire left front opening edge, from top of neckband to cast-on edge. Beg with row 1, work in rib as given for Neckband for 7 rows, ending with RS facing for next row. Cast off in rib.
Work to match Buttonband, picking up sts up right front opening edge and with the addition of 5 buttonholes worked in row 4 as folls: Row 4 (RS): Rib 3, *work 2 tog, yrn (to make a buttonhole), rib 27 ( 28: 29: 30: 31); rep from * 3 times more, work 2 tog, yrn (to make 5th buttonhole), rib 3.
Place centre of cast-off edge of sleeve to shoulder seam. Set in sleeve, easing sleevehead into armhole. Join side and sleeve seams. Sew on buttons to correspond with buttonholes. Block gently, following any yarn care instructions on the ball band.