Zara's notions of style really are quite curious. That ensemble just doesn't work and the hat is hideous. She often manages to make herself look indescribably cheap with her fashion choices, quite needlessly really as she has the potential to look great (great figure, nice face and hair).
Still it's hardly as if she has grown up in the palace of haute couture, is it? I imagine that nowadays she gets a frisson of fear every time she puts on something brand new, as that must have been a rarity of life when she was growing up at at Gatcombe Park with her endlessly recycling mother!!!