Peel and crush or grate the garlic. Pop the pork steaks in a shallow dish. Add half of the crushed garlic. Drizzle with 1 tbsp oil. Season with a little salt and pepper. Stir to mix. Set aside.
Trim the leek and halve it. Rinse out any grit. Finely slice it. Peel the potatoes. Chop into large, even-sized pieces. Drain the beans in a colander. Rinse. Set aside.
Heat 1 tbsp oil in a medium pan. Add the leek. Season with salt and pepper. Cover. Sweat over a low heat for 8-10 mins till soft and glossy. Stir occasionally.
While the leek cooks, put the potatoes in a pan. Cover with boiling water. Bring back up to the boil. Reduce the heat. Simmer for 10-15 mins till soft.
Give the leeks a good stir. Add the remaining garlic, the mustard, the beans and the tomatoes. Stir in the rest of the garlic. Simmer for 8-10 mins till the sauce is thick and glossy. Taste. Add more salt and pepper if you think it needs it. Cover and set aside.
While the beans simmer, heat a dry frying pan over a high heat. When hot, add the pork and fry for around 10 mins. Turn once or twice till the steaks are cooked through and golden. Pop on a plate. Cover with foil to rest for a few mins.
Finely chop the parsley leaves. When the potatoes are soft, drain them. Return them to the pan. Mash with 1 tbsp oil and most of the chopped parsley. Season with salt and pepper.
Warm the beans through for 1-2 mins if necessary. Serve the pork steaks with the mash and beans, garnishing with the remaining parsley.