For cornbread, preheat oven to 180C. Cook corn in boiling salted water until tender (10-12 minutes), drain, set aside to cool.Combine flour, polenta, cheese, baking powder, bicarbonate of soda, lemon rind, corn and 2 tsp sea salt in a bowl, stir to combine. Add buttermilk, eggs and butter, stir to combine, then spoon into an 8cm x 23cm loaf tin, greased and lined with baking paper, to 1cm below rim (there may be mixture left over). Smooth top, bake until golden and firm when pressed (45-50 minutes), cool in pan for 10 minutes, then turn out and cool on a wire rack. Just before serving, cut into thick slices and toast under a preheated grill until golden (1-2 minutes each side). Cornbread will keep, wrapped in plastic wrap, for 3 days.
Meanwhile, for green tomato relish, combine onion, lemon juice and garlic in a small bowl and stand until onion turns pink (5-6 minutes). Stir in tomato and olive oil, season to taste, set aside.
Heat oil in a frying pan over medium-high heat, add corn, bacon and onion, sauté until corn and onion are tender and bacon is golden (5-6 minutes), season to taste, keep warm.
Meanwhile, bring a saucepan of water to a simmer over medium heat, reduce heat to low, add a splash of vinegar. Crack eggs, in batches, into water and cook to your liking (5-6 minutes for soft-poached), remove with a slotted spoon and blot dry on absorbent paper. Serve warm with toasted cornbread, corn and bacon hash and green tomato relish.