First, the honeycomb. Prepare a tin or heatproof dish by lining with lightly oiled baking parchment. Heat the sugar, syrup, 100ml water and vinegar until it turns amber and reaches 150°C (the "hard crack" stage). Add the bicarb, stir well, then pour into your lined tin. Leave to cool. If you want it to be cut into ordered shapes, cut with an oiled knife when it's nearly at room temperature. I like it to look a little rough and tumble, so cut it when it's cool.