1) Preheat oven to 200C/Gas 6.
2) Place potatoes on a sheet tray, toss with oil, season with salt and pepper, and roast until golden and tender, about 30 minutes.
3) Meanwhile, in a saucepan cover chicken with water and bring to a simmer over medium heat. Poach until cooked through, about 15-20 minutes. Remove from poaching liquid, let cool for a bit and cut chicken into cubes.
4) In a large bowl, toss together potatoes, chicken and bacon with the celery, onions and garlic. Add the mayonnaise, mustard, paprika, herbs, salt and freshly ground black pepper, to taste. Mix until well combined.
Serve salad in butterhead lettuce cups. Roll up lettuce and eat.