We have to admit that we were as sceptical as the next person when we noticed cardigans slipping back into the collections of AW17. Sure, Helena Christensen's turn on the catwalk at Perry Ellis' '93 show makes a fantastic case for the button-up knit, layered over her checked slip dress, hair tousled, lace-up boots a-stomping. But now? How are we to wear the cardigan in 2017?