Grill the meat in a 150°C (302°F) Kamado BBQ for about 1-1.5 hr till an inside temperature of 56°C (132°F) and season with pepper and salt. Roast the garlic bulbs for about 45 minutes in the Kamado BBQ.
Wash the potatoes, cut in cubes, place on tinfoil with the mushrooms, sprinkle with oil and pepper and salt and roast for 10 min and season with lemon juice and thyme. Grill the bell peppers for 15 min and drizzle with oil, pepper and salt.
Leave the meat to rest for 10 min, cut in slices and serve with the vegetables, potatoes and cut garlic which is lovely to spread onto the meat.