The tribes take their dress codes into all areas. When riding (a key weekend activity is the Girls Hack, being as aesthetically pleasing as it is physically invigorating and sociable), a pretty horse and gorgeous clothes are as important as equestrian proficiency: the Country Princesses either opt for a preppy, old-school vibe and ride wearing pale yellow cotton jodhpurs from Harry Hall, with floral print blouses from Chloé or Dôen and boots from Schnieders, or, at the other extreme, there…

