I love your starter activity with the candle - I think you'd be OK with a real flame (check with Head first though!) just make sure its stood in a large tray of sand and is risk assessed! Maybe you could get the children to partner talk their experiences of fire first, I'm sure most will have seen a bonfire, some might even have a coal fire at home. Why not do a sensory exploration of what it would have been like to have been there when the fire was burning - empathy with the people who were there? You could show clips of fire, with sound effects playoing at the same time. You could have photos of fire and of the fire of london, smell pots with burnt paper in or struck matches so children could smell the fire. Hot water bottle so they could fel the heat!?! Not sure how you'd do the smoke! Get them to imagine they were on the street - discuss what they would see, what they would hear, what they would smell, what they would feel, what they would taste. Create word banks for each sense. Then maybe they could either write a letter describing what it was like or a diary entry.