It's finished, and it took less than 300g of yarn (it weighs 273g including the buttons).
There was slight pooling just above the waist, but that only lasted for a few rows:
Would I make it again? Yes, but I might do garter stitch instead of the ribbing at the neck and around the sleeves and on the button/hole bands as others have done. I think it's a pattern that could be modified to make it longer, perhaps leaving out the reverse stocking stitch triangles, or adding a stitch pattern. Overall, I'm very pleased with this and think it's something that DD1 will get a lot of wear out of, especially on her forthcoming cruising holiday with Granny and Grandad (lucky girl!).
Since finishing this, I've been spinning. I finished some burgundy merino which I'm planning on making into a Lucy bag. I'm not sure yet if I've got enough, or if I'll have to add some other yarn in as stripes. Once I've done some housework and ironing I'll wind it off onto my niddy noddy and work out how many metres I've got.
I also started spinning some yarn for a Colour Affection scarf/wrap, but more about that next time.