Preheat the oven to 180° C/356° F, with both top and bottom heat elements.
Lay the pork loin out on the kitchen top. Using a knife, make small incisions all over the surface. Insert the garlic into these holes to infuse flavor. Brush the entire surface with mustard.
Heat a skillet over medium heat. Sauté the bacon for 3-4 minutes until crispy. Remove from the pan and set aside.
In the same skillet, add a little olive oil if needed and sauté the onion for 2-3 minutes. Add the mushrooms, red bell pepper, sun-dried tomatoes, and oregano. Continue cooking for 4-5 minutes.
Pour in the white wine, season with salt and pepper, and stir well. Return the crispy bacon to the pan. Remove from heat and let the filling cool for 5 minutes. Spread the mixture evenly over the pork loin.
Roll the pork loin up tightly and secure with kitchen twine.
Brush the rolled pork loin with olive oil and mustard. Sprinkle with smoked paprika and oregano.
Heat a large skillet over high heat. Sear the pork loin for 1 minute on each side, until browned.
Place the roll in a baking tray lined with parchment paper, then cover it with another sheet of parchment paper and aluminum foil. Bake for 1 1/2 hours, then uncover and bake for an additional 20 to 30 minutes.
Let the roll cool for 10 minutes, remove the twine, cut into portions and serve - either with mash or baked potatoes.