I love, love, love how much attention your derriere is getting on this blog and in the eating establishments of the Trafalfar Square environs. It would be a shame to put it under wraps now. Although I do love a playsuit. And that one looks quite 40s and demure so I say get it.
As to the "tunic" I think it is the folks at To'Sho who are deluded, not you, because that thing looks positively matronly in comparison with most of the dresses you drape yourself in. It is a dress, they just got it wrong.