For the griddled scallops and chicory, remove the scallops from their shells and rub with half the olive oil.
Heat a griddle pan and cook the scallops for 30 seconds on each side. Clean the scallop shells thoroughly, then put the griddled scallops back in their shells.
Rub the chicory with the remaining oil and cook on the griddle for 2-3 minutes, until tender.
For the mustard hollandaise, place the vinegar and peppercorns into a small saucepan, bring to the boil and boil until reduced to one tablespoon of liquid. Remove the peppercorns and set aside.
Place the egg yolks into a small food processor and blend. With the motor running, gradually add the vinegar reduction, then add the melted butter one tablespoon at a time. Stir in the mustard and season, to taste, with salt and freshly ground black pepper.
Preheat the grill to medium.
Place the scallops in their shells onto a baking sheet, pour over the hollandaise and place under the grill for 1-2 minutes, or until bubbling.
To serve, place the chargrilled chicory onto a serving plate and top with the scallops in their shells. Serve immediately.