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? How old must you be to enter The York Dungeon? Do I get a discount by booking online? How do I access Booking Portal?