Like Dave, I like the portobello dress too. If you have big hips (like me!), I’d stick to your usual size. Otherwise the material will stretch across your bum and you lose the little swish effect.
I’m very torn about the Nina dress. The top of the 12 has loads of excess material. The bottom part is fine. The top of the 10 is a good fit, but the bottom part loses its folds and is just material stretched across my bum in an unflattering way. I suppose the bigger top half is better than a smaller bottom half??? What do you guys think?