Pre-heat the oven to 180°C/gas mark 4. Place a 500g beef roasting joint on a rack, season and place in the oven. Roast in total for around 55 minutes for medium or slightly longer for well done. Remove from the oven, cover with foil and leave to rest for around 10 minutes. While the beef is cooking, peel 800g of potatoes, cut them into large pieces and par-boil for around 7 minutes. While the potatoes are boiling, heat 2 tbsp of sunflower oil in a roasting tin. Drain the potatoes, and place them in the tin, brush with the oil, then pop into the oven for around 45 minutes until crisp and golden, turning the oven up to 200°C/gas mark 6 once the beef is removed. Meanwhile, pop 8 ready-made Yorkshire puddings into a tin and cook according to the instructions on the packet. Serve the beef, potatoes and Yorkshire puds with steamed seasonal veg, gravy and horseradish sauce. Finish with a lovely bowl of fruit salad each.