Wrap a towel, thick cloth or glove around the hand in which you wish to hold the oysters. Working over a bowl to catch any juices, hold an oyster firmly so that the hinge area is exposed and the flattest side is uppermost. Take an oyster knife or other short, strong knife and insert the tip in the crack between the shells near the hinge.
Work the knife around in the shell until you feel it cut the muscle that attaches the oyster to the top shell. Turn the knife upwards to prise the shell apart. Remove the flat top shell and set the curved bottom section cupping the muscle and juices aside on a baking tray. Repeat with the remaining oysters.
Heat the tandoor or grill. Pare the zest from the lemon and cut the flesh into wedges.
In a small, nonstick frying pan, slowly heat the chopped bacon to release its fat gently. Cook lightly for 5 minutes, stirring frequently, until just beginning to brown. Stir in the lemon zest, parsley and some black pepper.
Divide the bacon between the oysters, pour over the reserved juices and place under the hot grill for 3 minutes, until the bacon is crisp and the oysters are cooked. Squeeze a little juice from the lemon wedges over the top and serve at once with wholemeal bread.