It's a size 2 = UK10 but is very roomy. I'd say it is a good fit for UK12 (oversized) - UK16 (still a bit oversized!).
I'd also say it is a better fit for taller women as the sleeves are long. But you could always get them taken up if too long for you.
Sits upper thighs in length.
There are no buttons - it closes with a front flap feeding through a hole.
It's 70% lambswool/ 20% angora/ 10% cashmere.
In excellent condition.