Preheat the oven to 200°C (400°F), Gas Mark 6, and bring a large saucepan of water to a gentle simmer. Place the cherry tomato vines in an ovenproof dish, drizzle with the balsamic syrup or glaze, scatter with the basil leaves and season to taste. Cook in the preheated oven for 8 minutes, or until the tomatoes begin to collapse.
Meanwhile, add the vinegar to the pan of simmering water, carefully break 2 eggs into the water and cook for 3 minutes. Remove with a slotted spoon and keep warm. Repeat with the remaining eggs.
Divide the spinach between 4 serving plates and place a poached egg on top of each. Arrange the tomatoes on the plates and drizzle the juices on top. Serve immediately with wholemeal toast.