www.hush-uk.com/womenswear/womenswear_1/dresses_skirts/tina_dress_charcoal_marl.htm
I don't think there's any official policy on what to wear, my boss wears a suit (male) and my five colleagues all female are smart-ish, no jeans for example. Mostly everyone wear trousers, I'm the only one who doesn't as I find dresses easy to throw on but it's hard to tell if this dress is a bit too casual. Am a size 14 and early forties.