We all have those scents that give us instant flashbacks to childhood, for me it is the zingy, almost effervescent smell of citronella, which is so widely used in South East Asia as an insect repellent that just touching a plant instantly transports me back to the Chinese New Year fireworks in my grandparents back garden. And I promise you, you don’t need to have ever been to Asia to feel totally engulfed by its rich, exotic scent.