Heat a large frying pan over a medium heat and dry fry the pancetta for 2-3 minutes, until crisp and golden. Crumble 2 of the rashers and set the rest aside.
Stir 2 tbsp of the chives into the beaten eggs along with the crumbled pancetta. Dip the bread slices into the egg mixture, turning to coat well.
Heat half the oil in the pan and cook half the eggy bread for 2 minutes on each side, until lightly golden. Keep warm and repeat with the remaining oil and bread. Meanwhile, preheat the grill to medium and grill the tomatoes on a baking sheet for 5-10 minutes.
Serve the eggy bread topped with the grilled tomatoes and crisp pancetta rashers. Garnish with the remaining chives.