Start by shredding your leftover roast chicken in a large mixing bowl. Add a dollop of mayonnaise and a spoonful of Dijon mustard, then sprinkle in chopped chives, salt, and pepper. Mix everything together until well combined.

Cut the focaccia in half horizontally and preheat a skillet over medium heat. Place the cut side of the focaccia down in the skillet and toast for about 3-4 minutes, or until golden brown and lightly crisp.

Spread a generous layer of basil pesto on both halves. On one half, scoop the chicken mixture evenly, followed by crispy bacon strips and a handful of fresh rocket. Place the other half on top, pressing down gently.

Cut the panini in half for easier handling. Serve immediately while warm.