With country music festival attendances soaring and US artists selling out tours, are British and Irish audiences ready for “the full Southern experience”? “There’s a certain magic with country music in the UK right now,” says Anna-Sophie Mertens, smiling in hi-vis from the build at State Fayre, the UK’s newest festival for country fans. It is located in Chelmsford but styled like the American South – think clapboard, rusted metal and water points disguised as retro gas stations – and this weeke