I have an animal print Project D dress very similar to this one, with the same sheer sleeves, fitted shape and v-neck. I wore it to an interview a few months ago, and I got the job! I would say the dress had nothing to do with it, but I think it may well have sealed the deal. If you want to prove my success wasn't a fluke, this baby is down to £36 from £120 at Simply Be. At a price like that, you won't be surprised to know that available sizes are limited, but move quickly and you might get lucky.
If you work in the kind of office where jeans are allowed, a collarless jacket like this one from Bon Marche (£22, currently in stock up to an XL which fits size 24 - 26) will smarten them up immediately, but is a bit more unusual than the obvious choice of a blazer. Don't fear the frumpiness of a style like this - if it's good enough for Coco Chanel, it's good enough for you. Just ditch the pearls in favour of a more playful necklace (the chunkier the better), mess your hair up a bit and wear something colourful underneath.
Carmakoma describes this as a 'great fitting dress' (£84.85) but if that's not enough to sell you on it, then maybe the little shoulder cutouts will seal the deal? Even the most conservative employers can't complain about a tiny flash of upper arm flesh, and those tiny details are vital, as they stop this simple black shift from being a sack.
For a slightly smarter alternative to leggings or skinny jeans, these Castaluna trousers (£39) go up to a size 32 and they're magic. So many plus size bottoms are bootlegs or wide palazzo pants, which are fine if you like a baggier look, but not everyone likes that wider silhouette. There are elasticated panels in the sides of these for comfort and stretch, and a slim cut down to the ankle. Grab them in black, navy or taupe (or all three).