Can I pre-book online with my 2 for 1/promotional voucher? All tickets, including promotional vouchers, must be pre-booked in advance with limited numbers available, please click here to redeem your promotional voucher. Related articles Is my 2 for 1 voucher valid at the York Dungeon? How do I use my Kellogg's Grown Ups Go Free voucher online? Can I use a 2 for 1/promotional voucher in conjunction with another offer or promotion? I have purchased a ticket from a 3rd party how do I book my visit? How many people are on each tour?