Place the potatoes in a large saucepan, then pour in enough water to cover them. Bring to boil over medium high heat. Let it simmer for 6 minutes. Add ½ tsp salt to the pan. Add the beans and cook for a further 3 minutes. Then tip in the peas and cook for 2 minutes more until all the vegetables are just tender. Drain.

Mix all the dressing ingredients in a large bowl and season with black pepper.

Brush oil over the steak and season well with salt and black pepper. Heat a non-stick frying pan over a high heat and cook the steak for 4 minutes on one side and 2-4 minutes on the other to your liking. Transfer to a plate to rest.

Mix the warm vegetables into the dressing until well coated, then add the lettuce and toss again. Arrange the vegetables on a serving platter. Slice the steak, pour any dressing left in the bowl over the meat and add to the salad. Sprinkle sunflower seeds. Serve while still warm.