It's a big scary how fast Ravi's eyes widen with blissful wonder, reaching out to grab hold of Helen's hand so that he can squeeze it. "Are you telling me that I've had transitive sex with Nikola Tesla?" he demands, his words brimming with the kind of excitement that generally precedes a pre-teen girl squealing about Harry Styles and the rest of One Direction, but honestly, can you blame him?

"Was he a good shag? I need to know," Ravi admits, feeling like a gossipy old hen, but completely unable (and unwanting) to help that.