Barbacoa lamb tacos

Name: Barbacoa lamb tacos
Ingredients: 3 ancho chillies, stem and seeds removed; 2 guajillo chillies, stem and seeds removed; 2 plum tomatoes, roughly chopped; ½ onion, chopped; 4 garlic cloves, peeled; 1 tbsp sea salt flakes; 1 tsp ground cumin; ½ tsp ground cinnamon; ½ tsp dried oregano; 5 black peppercorns; 2 cloves; ½ leg of lamb on the bone, approx. 1.2kg/2lb 10oz, at room temperature; 500ml/18fl oz lager; 15 corn tortillas, warmed; small bunch fresh coriander, chopped; 1 red onion, finely chopped; 2 limes, cut into wedges; spicy salsa of your choice