Mix together the oil, wine, cumin, paprika and black pepper in a small bowl.
Place the lamb in a shallow dish and make small slits over the surface. Push a slice of garlic into each slit. Spoon over the spice mixture and spread it all over the lamb. Cover loosely with clingfilm and leave to marinate in the refrigerator for several hours, occasionally spooning the marinade over the meat. Place the lamb on the lower rack of the halogen oven.
Set the temperature to 250°C (482°F) and roast the lamb for 15 minutes. Reduce the temperature to 200°C (392°F) and roast for a further 40 minutes, spreading with the leftover marinade in the dish during cooking. (The lamb will be slightly pink in the centre; cook for a little longer if you prefer it well done.)
Transfer to a carving platter or board, and leave to rest for 20 minutes before carving. Serve with a Greek salad and warm pitta bread.