Remove tail ends of bacon rashers, roll up and secure with a toothpick. Place in the fridge until needed. Dice remaining bacon.
Preheat oven to 200°C Place stock in a pan over medium-high heat and bring to the boil. Reduce heat to low and simmer.
Heat oil in a pan over medium heat. Stir leek and diced bacon for 2-3 minutes, until leek is soft and bacon starts to colour. Add garlic and rice, and stir for 2 minutes. Add wine and stir until absorbed. Add stock a ladleful at a time, stirring until absorbed between additions, until rice is al dente (this should take about 15 minutes).
Meanwhile, place tomatoes and bacon curls on a baking tray, drizzle with oil and season tomatoes. Roast for 10 minutes or until tomatoes are just soft and bacon is crisp. Set a few tomatoes aside. Remove stalks from remaining tomatoes and stir into risotto with grated parmesan and parsley, then season. Serve risotto topped with butter and garnish with tomatoes, bacon curls and shaved parmesan.