Heat the olive oil in a large pan over a medium heat. Add the sliced bacon rashers and cook for 5-6 minutes, until golden brown. Add the diced onion, carrot and celery and cook for 10 minutes, until softened and golden brown. Add the beef mince and turn the heat up for 6-7 minutes to brown it all over. Add the garlic, tinned tomatoes, tomato purée, beef stock, bay leaves and oregano. Mix everything together well and season. Cover with a lid and simmer for 30 minutes, stirring occasionally, then remove the lid and simmer for a further 15-20 minutes, until thickened up. Set aside 150g to use in the balls.
Heat the butter and oil in a medium saucepan over a low/medium heat. Place the stock over a low heat to keep it warm. Add the diced onion and cook gently for 12-15 minutes, until completely soft. Add the risotto rice and stir well to coat, then cook, stirring, for 2 minutes. Add the wine and leave it to evaporate, then add a ladleful of the stock. Stir and replace the lid. Continue adding stock and stirring for 25 minutes until all the stock has been absorbed, then season the risotto and stir through the parmesan. Line a wide baking dish with greaseproof paper and add the risotto, spreading it out well to allow it to cool.
Make sure the risotto rice and 150g ragu are completely cold before you start to shape them. Using a large spoon or ice cream scoop, place large balls of the rice mixture on to one hand and flatten out with the other hand. Place a small spoonful of the ragu mixture in the middle, then shape the ball around it. Repeat with the remaining rice and ragu mixtures, until you have 15 balls.
Place the flour, eggs and breadcrumbs on three separate plates. Roll each ball first in the flour, then the egg, followed by the breadcrumbs. Place these on a baking tray lined with greaseproof paper, then put this in the fridge to firm up for 30 minutes.
Meanwhile, make the tomato dipping sauce. Heat the oil in a saucepan over a medium heat and add the onion. Cook for 10 minutes, until just softened, then add the garlic and cook for a further minute. Add the tomatoes and balsamic vinegar and cook for 5 minutes, until softened, then set aside to cool slightly. Once cooled, place in a food processor and blitz until smooth. Stir through the basil.
Preheat the oven to 160°c/fan 140°c/gas mark 3. Heat the oil in a high-sided pan until it sizzles and floats when a breadcrumb is dropped into it. Add the arancini balls to the hot oil in batches and cook for 4-5 minutes on each side, until deep golden all over. Line a baking tray with kitchen paper to absorb excess oil, then place the arancini balls on top and keep warm in the oven while you cook the remaining balls. Serve with the tomato dipping sauce.