Pulled pork with spicy coleslaw

Name: Pulled pork with spicy coleslaw
Ingredients: oil, for greasing; 2kg/4lb 6½oz pork shoulder; 1 tbsp chilli flakes; 1 tbsp wholegrain mustard; 200ml/7¼fl oz white wine vinegar; 250ml/9fl oz cider; 3 onions, thinly sliced; 6 cloves garlic, thinly sliced; salt and freshly ground black pepper; half white cabbage, finely chopped; 2 carrots, grated; 2 red onions, thinly sliced; 1 red chilli, seeds removed, finely chopped; 175g/6oz mayonnaise; 1 lime, juice only; 1 tbsp soy sauce; 8 soft white bread rolls; 4 tbsp ready-made barbecue sauce