LONDON — In his third season for Burberry Prorsum, creative director Roberto Menichetti came up with the standout collection of London Fashion Week thus far. And he did it without any runway theatrics. At a breakfast presentation on Thursday, he gave the classic plaid a hip twist, mixing it with other patterns and pairing it with such looks as a bustled frock. Here, his patterned jacket and dress. For more on London, see pages 12 and 13.