1. Trim the outer edges of the sole using a scissors and, if preferred, cut off the head (the sole can also be cooked head on, although your frying pan may be too small). Sprinkle the flour on to a flat tray and coat the sole in it on both sides, shaking off any excess flour. Season both sides with sea salt.
2. Heat the vegetable oil in a pan (either cast iron or non stick), until the pan starts to slightly smoke. Gently place the sole in the pan and fry on one side until golden brown (two minutes). Using a fish slice, turn the sole and fry on the other side for two minutes. Reduce the heat and add the butter. Once the butter is foaming, use a spoon to baste the butter over the fish until it is cooked (use a fork to pierce the sole, if it goes straight through, its cooked. If there is resistance, it needs a little more time). Remove the sole from the pan and allow to rest on a tray.
3. Add the diced bacon to the pan and cook in the butter until golden. Add the vinegar and reduce for five seconds, and then add the capers, juice of one lemon and chopped parsley. Pour over the sole and serve with sliced lemon (seasoning with salt as desired).