Sweet potato shepherds pie

Name: Sweet potato shepherd’s pie
Ingredients: 1 tbsp rapeseed oil; 2 onions, finely chopped; 2 garlic cloves, chopped; 2 carrots, grated or finely diced; 2 tbsp fresh thyme leaf; 400g pack extra-lean minced lamb or beef; 85g red lentil; 350g swede, diced; 2 tbsp plain flour; 750ml reduced-salt beef stock; 200ml red wine; 350g potato, diced; 650g sweet potato, diced; 150g 0% plain probiotic yogurt; generous grating of nutmeg; green vegetables, to serve