Leg of mutton with roasted tomato orzo

Ingredients

• For the mutton:
• 1.3kg Field & Flower leg of mutton, bone-in,
• 2 large carrots, roughly chopped
• 3 sticks of celery, roughly chopped
• 2 onions, roughly chopped
• A few sprigs of fresh thyme and rosemary
• 300ml white wine
• 700ml hot chicken or lamb stock
• 1 tbsp plain flour
• 1 tbsp softened butter
• 1 heaped tsp Dijon mustard
• Olive oil
• For the orzo:
• 75g Yorkshire fettle cheese, crumbled
• 200g cherry tomatoes, halved
• 1 red onion, finely chopped
• 2 cloves garlic, chopped
• 300g orzo
• 600ml chicken stock
• ½ lemon, finely grated zest and a squeeze of juice
• Small handful each of parsley and basil, chopped
• Seasoning to taste