1) For the marinade, mix 1 tbsp olive oil, 1 tbsp mild curry powder, ½ teaspoon ground ginger, 1 tsp chilli powder, and the garlic powder, soy sauce, tomato ketchup, HP sauce, teriyaki sauce, paprika, ground turmeric, garam masala, coriander powder, ground cumin, mixed herbs and black pepper in a glass bowl and add the beef cut into pieces. 2) Rub well into the beef and leave to marinate for 4 hours or overnight in the fridge. 3) To make the curry, fry the marinated beef in oil on a medium to high heat, until brown on all sides. 4) Add the potatoes and onions and fry for 1 - 2 minutes until well coated with the spices. 5) Add the rest of the dry ingredients and fry, stirring continuously for a 2 - 3 minutes. Add more oil if needed. 6) Add the stock and enough boiling water to cover the beef and stir to mix. 7) Cook on a low heat, simmering, for 1 hour or until meat is tender. 8) Mash some of the potato pieces to thicken the sauce. 9) Serve with rice or roti.