To make the lamb patties, mix lamb, parsley, onion, salt, pepper and allspice in a bowl until just combined (use hands and do not overwork mixture or patties will be tough) Form into 4 patties. Preheat grill; grill the bread. Brush both sides of the bread slices with oil (2 tbsp total for all) and grill, turning once, until golden on both sides, 1-2 minutes total. Rub 1 side of each piece of toast with the cut side of remaining garlic cloves and season with a pinch of salt. Grill patties on a hot lightly oiled grill rack, turning over once, until nicely browned on the outside but still slightly pink in the centre (5-7 minutes total depending upon the grill).