Mix all the marinade ingredients ( orange, soya sauce, sugar, mustard, 2 tsp garlic ) in a non-metallic dish and add the steaks. Cover and chill until required, turning to coat well.
Meanwhile, cook the potatoes until tender, then mash until fluffy with the butter and milk. Place the cabbage, onion, garlic and oil into a pan.
Saute while stirring for around 3 minutes until tender. Mix in the mashed potato, parsley, salt and pepper.
Place steaks onto a grill tray and cook under medium-high for 3-4 minutes each side, basting at times with marinade.
Spoon the potato into an oiled ovenproof dish.
Grill until golden and serve alongside the sticky steak.