1. Remove stalks from fresh tomatoes. Using a small, sharp knife cut a cross in each one. Put whole tomatoes into a bowl and cover with boiling water. After 10 seconds remove with a slotted spoon and plunge into cold water. Peel away skins and chop tomatoes roughly.
2. Remove stalks from red pepper and green pepper. Cut peppers into quarters and place, skin side up, on a baking tray. Grill for 8 minutes, or until the skins blacken an blister. Drop into a plastic bag, seal and leave to cool for 5 minutes. When cook, peel off skins. Deseed and cut each quarter into strips.
3. Peel onions and garlic cloves and finely chop with a sharp knife. Heat olive oil in a heavy-based saucepan. Add onion and garlic. Cook for 4 to 5 minutes, or until tender but not browned.
4. Add chopped tomatoes, peppers, tomato purée, red wine vinegar, sugar and thyme. Cook over low heat for 5 to 10 minutes or until liquid has the consistency of tomato sauce - not too thick and not too runny.
5. Cut bread into 8-10 (1 cm) slices. Cut off crusts and discard. Cut a circle from one bread slice to fit the bottom of a 1,1 litre pudding basin. Cut remaining slices into (4 cm) fingers. Put bread circle in base of basin. Arrange bread fingers slightly overlapping around sides.
6. Spoon tomato and pepper filling into the prepared basin. Cover filling with remaining bread fingers. Overlap them slightly, making sure there are no gaps and that filling is completely sealed in.
7. Cover basin with greaseproof paper then foil. Put a small plate, just smaller than the basin, on top of the foil and weigh pudding down. Do this with either kitchen weights or an unopened can of soup or a basin of cold water. Chill for 24 hours.
8. The next day, in a small bowl mix together Greek yoghurt, milk and lemon juice until well blended. Stir in chopped basil, chives and parsley. Cover and keep in fridge until required.
9. Remove weights, paper and foil from the pudding. Using a palette knife, carefully ease bread away from side of basin. Put serving plate on top and quickly invert. Remove basin. Decorate pudding with sprigs of basil and parsley. Serve with yoghurt dressing.