Yes to fireworks, although they were Wednesday when I went. Usually go second week in December. It's bloody freezing and you do not want to be stood waiting for the land train cold so take thick warm coats. The logs for the fires they use are sold in Asda for about £3. Buy them in the supermarket and take them with you. Take a slow cooker if you know how to use one, coming home to a stew and not having to piss about with a grumpy child trying to eat in a resteraunt is amazing. Travel mugs so you can take hot chocolate/tea/coffee out with you. Longleats pool is huge, so there's plenty to do.