Striped hot water bottle cover - crochet pattern

One of the good things about a cold winter's night is snuggling up in bed with a toasty warm hot water bottle. Of course, you need a good cover for your hottie so you can cuddle it without burning yourself. Here is an easy crochet pattern, worked in double crochet (US), which buttons at the bottom for ease of removal.

MATERIALS:
Slightly more than 2 50g balls of plain yarn (I had to join a 3rd ball just to do the last couple of rounds, annoyingly). I used a fairly chunky, slightly lumpy chenille type yarn.
1 ball contrasting yarn for stripes (I used a variegated self striping yarn).
6 mm crochet hook
3 buttons, approx 1 inch across

ABBREVIATIONS:
ch = chain
dc = double crochet
dc 2 tog = double crochet 2 together (decrease).

PATTERN:
In colour A, ch 54, join to make ring.
Rnd 1: ch 3 (counts as 1 dc), 1 dc in each chain (54 dc)
Rnd 2: ch 3 (counts as 1 dc), *ch 1, skip next dc, 1 dc in next 9 dc* twice, ch 1, skip next dc, 1 dc in next 27 dc, join in 3rd ch.
Rnd 3: ch 3, 1 dc in each dc (1 dc in each ch 1 space) (54 dc)
Rnd 4: Join colour B.
You don't have to fasten off with colour A - just bring the yarn up the inside of the rows, to join on each time you change colour (see below).
Ch 3, 1 dc in each dc (54 dc)
Rnd 5: Join colour A. Ch 3, 1 d in each dc (54 dc)
Rounds 6 - 22: continue as for Round 5, alternating between 2 rounds of colour A and 1 round of colour B.
Rnd 23: Join colour A. ch 3, dc 2 tog in next 2 dc, dc in next 22 dc, dc 2 tog in next 2 dc twice, dc in next 23 dc, dc 2 tog in next 2 dc, join.
Rnd 24: ch 3, dc 2 tog, dc in next 20 dc, dc 2 tog twice, dc in next 21 dc, dc 2 tog, join.
Rnd 25: Join colour B. ch 3, dc 2 tog twice, dc in next 14 dc, dc 2 tog 4 times, dc in next 15 dc, dc 2 tog twice, join.
Rnd 26: Join colour A. ch 3, dc 2 tog twice, dc in next 10 dc, dc 2 tog 4 times, dc n next 11 dc, dc 2 tog twice, join.
Rnd 27: ch 3, dc 2 tog, dc in next 10 dc, dc 2 tog twice, dc in next 11 dc, dc 2 tog, join.
Rnd 28: Join colour B. ch 3, 1 dc in next 25 dc, join.
Rnd 29: Join colour A. ch 3, 2 dc in next dc, 1 dc in next 12 dc, 2 dc in next dc, 1 dc in next 11 dc, join.
Rnd 30: ch 3, 1 dc in next dc, 2 dc in next dc, 1 dc in next 13 dc, 2 dc in next dc, 1 dc in next 11 dc, join.
Rnd 31: Join colour B. ch 3, 1 dc in next 2 dc, 2 dc in next dc, 1 dc in next 14 dc, 2 d in next dc, 1 dc in next 11 dc, join.
Rnd 32: Join colour A. ch 3, 1 dc in next 3 dc, 2 dc in next dc, 1 dc in next 15 dc, 2 dc in next dc, 1 dc in next 11 dc, join. Fasten off.

Bringing the yarn up between each colour change.

FINISHING OFF:
Sew in all loose ends of yarn. Lay cover flat and align buttonholes so they are evenly placed along the bottom. With a fabric marker, make a mark through the buttonholes onto the back side. Stitch the buttons on securely - if neccessary, use a small dot of glue to hold the knot in place. You won't need to block this - but be aware that if you use a wool or wool blend yarn, the heat of the hot water bottle will probably felt it a bit.