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 How do I use my National Rail Days Out 2 for 1 voucher? How do I use my Kellogg's Grown Ups Go Free voucher online? Can I use my Tesco Clubcard for entry into The Edinburgh Dungeon? Is my 2 for 1/promotional voucher valid at The Edinburgh Dungeon? Can I use my Nectar Points for entry into The Edinburgh Dungeon?