Heat the oven to 180C/160C fan/gas 4. Remove any loose skin from the garlic bulbs and slightly fan the cloves without removing them from the root. Put on a sheet of foil, then drizzle with the 2 tbsp oil and sprinkle with salt. Wrap in the foil, and roast in the oven for 30-35 mins until soft. Leave to cool.

For the marinade, put the prunes in a jug with 100ml boiling water for 10 mins until soft. Squeeze the roasted garlic flesh from the skins into the jug, then add the rest of the marinade ingredients. Whizz together using a hand blender until smooth.

Put the lamb in a large baking dish. Make small incisions with a sharp knife, then pour the marinade over, massaging it into the holes. Cover with foil and leave to marinate in the fridge for at least 30 mins or up to 24 hrs.

Turn the temperature up to 200C/180C fan/gas 6 and put the lamb in the oven, immediately turning it down to 150C/130C fan/gas 2. Cook for 3-4 hrs, until the lamb has pulled away from the bone. Remove from the oven.

Pour the juices into a jug, then skim off the layer of fat. Turn the grill to high, then brown the lamb for 10 mins. Remove, loosely cover with the foil, and rest for 20 mins before shredding the meat.

Add 1 1/2 tbsp of the juices to a saucepan over a medium heat and mix in the flour or cornflour. Cook for 3 mins, stirring, until it starts to colour, then add the wine, and simmer to reduce the liquid by half. Stir in the remaining meat juices. Taste for seasoning, then serve with the lamb.