I know, I know… I can’t quite believe I’m recommending that you dress like Sienna Miller either. Or, indeed, that you wear something calling itself a "pinny". But still… while this kind of shapeless style would make me look like a toddler, there’s no denying that ol’ Sienna here is wearing it well. You’ll find a similarly styled dress at Dorothy Perkins for £20, and you can pick up the silver sandals there too – they’re £18.
Those dresses have been available here for a few months. They never really became popular. I know two girls who have the and in fairness, it looks good on both of them. They opted for it in gey, though when grey was popular (up until about 4 weeks ago). Apparently they were available in Penny’s/Primark.