My mother recently visited 'The Alnick Garden' in Northumberland, which is near the Alnick Castle. It is a charitable trust, who have made the most amazing garden with incredible things in it!. http://www.alnwickgarden.com/ It would be fantastic for kids. Amongst other attractions it has the worlds largest treehouse, (which you can also arrange to have Christmas dinner in from 1st-24th Dec!), the grand cascade (amazing fountains and massive tiered structure with 7,260 gallons of water per minute), poison garden, woodland walk, bamboo labyrinth and loads more. From what I heard it has all kinds of things for those interested in science and nature, (adults and kids), is a real feat of engineering, and a gobsmacking day out. Have a look....I hear even the toilets are amazing! There are loads of things on over Christmas, Carol singing from ENORMOUS choirs, father xmas, special screenings of the Snowman, lantern making or Boxing Day Jazz brunch! and lots more. If you visit, please post how you get on, as I am desperate to go myself, with or without the kids!