Am linking to La Redoute as they have a £15 off £20 spend offer in promotional codes just now.
Lovely colour
They also had some quite nice looking cowl neck sweater dresses in River Island (I know!) but can't link to individual items (near the end of the "day dresses" section).
Not sure about the frill on thisi but like the teal colour.
Loving this one but not sure how you would wear something underneath because of the back.
Apologies, I don't think I'm quite getting it right for you.
Dorothy Perkins has some interesting stuff online from a make called Culture which you might want to look at too.