Simmer honey, juices, vanilla seeds and cinnamon in a large deep-sided frying pan over medium-high heat until well combined and syrupy (7-8 minutes). Add pears and simmer, turning occasionally, until caramelised (10-15 minutes). Divide pears and pan juices among 4 buttered shallow 1½ cup-capacity ovenproof dishes and set aside.
Meanwhile, for bread and oat crumble, preheat oven to 160C. Spread cubed bread in a single layer on an oven tray and bake until dry but not coloured (5-6 minutes). Remove from oven and cool. Increase oven to 180C. Coarsely crumble bread with your fingers into a small bowl, add oats, sugar and cinnamon and mix to combine. Drizzle over melted butter and mix well with your hands to evenly coat dry ingredients. Scatter over pear mixture in dishes, then bake until bubbling and golden (10-15 minutes). Serve immediately with natural yoghurt.