Preheat the oven to 160ºC/140ºC fan oven/Gas Mark 3. For the pulled pork, add the oil to a roasting tray and sit the pork on top. Spread the mustard over the top and scatter over the chilli flakes, salt and freshly ground black pepper. Pour over the vinegar and cider or apple juice then scatter over the onions. Place a piece of nonstick baking parper over the top then wrap a piece of foil over the top, sealing around the edges of the tray. Place in the oven for 3 hours. Remove the paper and foil and cook for a further 1 hour until the pork is meltingly soft. To make the apple sauce, put all of the ingredients in a saucepan and cover with a lid. Cook for around 10-15 minutes until the apples have softened and are breaking up. Briskly stir for a smoother texture.To make the coleslaw, mix everything together and season with salt and pepper. To serve, ?pull' the pork by shredding the meat using two forks and serve in split bread rolls topped with the warm apple sauce and coleslaw on the side.