With RS facing, using 3.25mm needles and A, pick up and knit 164 ( 166: 166: 170: 172) along left front, from start of neck shaping to cast-on. Work 12 rows in moss st. Cast off in patt.
With RS facing, 3.25mm needles and A, pick up and knit 164 ( 166: 166: 170: 172) sts along right front, from cast-on to start of neck shaping. Work in moss st for 5 rows, ending after a WS row. Buttonhole row (RS): Patt to last 36 sts, *cast off 4 sts, patt until there are 10 sts on RH needle after last cast-off; rep from * once more, cast off 4 sts, patt to end. Next row (WS): Work in patt, casting on 4 sts over each set of cast-off sts. Work 5 rows more in moss st. Cast off in patt.
Using 3.25mm needles and A, cast on 35 ( 39: 43: 47: 51) sts. Work 1 row in moss st. Cont in moss st, casting on 5 ( 6: 6: 7: 7) sts at beg of next 10 rows, then 7 ( 7: 8: 8: 8) sts at beg of foll 2 rows. 99 ( 113: 119: 133: 137) sts. Work even in moss st until piece meas 8cm from last cast-on. Cast off in patt. Weave loose ends back into own colours. Join shoulder seams. Join side seams and sleeve seams. Set sleeves into armholes. Attach collar. Sew buttons opposite buttonholes. Block lightly to measurements, following any yarn care instructions on the ball bands.