Cut the sea bream at the bottom of the belly and brush with mustard. Cut the halloumi into slices. Fill the fish with 2 lemon wedges and halloumi and the herbs. Brush the skin of the fish with olive oil, then season with salt and pepper.
Grill the sea bream on each side for about 5 minutes on a mild glow. If the tail fins can be pulled out, the fish are well done.
It goes well with fresh herb baguette and stuffed peppers.