There is a sign pinned to the wall of Oh Wonder’s recording studio in south-east London, a pact of sorts, signed by the band’s two members, Josephine Vander Gucht and Anthony West, in the winter of 2012. It isn’t a checklist or a plan so much as a setting down of shared dreams for their musical careers. “We wrote it to say that we’re dependent on one another,” explains Josephine. “That there are things we want to achieve, and we can help each other get there.”