I have a Kellogg’s snack pack voucher (e.g Fruit Winders, Rice Krispie Squares), how do I pre-book my ticket? To pre-book your Grown Ups Go Free ticket (i.e. buy one child ticket get one free adult ticket) click here. To pre-book your Mates Go Free ticket (i.e. buy one adult ticket get one adult ticket) click here. Related articles How do I redeem my Kellogg's Cereal Pack Grown Ups/Mates Go Free voucher? I am a member of National Trust; would I be entitled to free entry? How do I redeem my Tesco Clubcard Vouchers at Warwick Castle Resort? Do I need to book online in advance if I have a promotional voucher? How do I use the National Rail Days Out Guide 2 for 1 offer?