Is there any evidence that the Vampire's Wife dress did win a Vogue 'Dress of the Decade' award - or that there is even such a thing as a Vogue 'Dress of the Decade' award?
I can't see anything on Vogue's webpage or social media about such an award. Perhaps yet to be announced?
All that Google can tell me is that the headline of a, typically hyperbolic, Vogue article about the Vampire's Wife recent collaboration with H&M, was 'The Dress of the Decade Has Hit the High Street'. No mention of there being an actual 'gong' (as SH terms it) or that the reference is to any particular VW dress.
Google also tells me that a few months earlier, Vogue described a different dress as the 'dress of the decade'. The headine of an article - by the same writer - about Realisation Par dresses was 'Forget The Dress Of The Summer, These Are The Dresses Of The Decade'.