Gently poach the chicken in heated stock for 10-15 minutes, then place in a bowl.
Pulse shallots, garlic, and herbs in a blender until finely chopped.
Blend in ketchup, then slowly add oil, lemon juice, and Worcestershire sauce until combined.
Pour the herb dressing over the chicken and leave to cool and marinate.
Boil new potatoes in salted water until tender, then drain and chill.
Blanch asparagus in boiling salted water for 2-3 minutes, then drain and chill.
Chop shallots, dice potatoes, and combine with asparagus and snipped chives.
Folder in mayonnaise, season to taste, and refrigerate.
Place marinated chicken on a serving plate, pour over dressing, and add the potato salad.
Garnish with fried cherry tomatoes and basil leaves before serving.