Instructions:Found this today. Valid until 30.06.2008, so plenty time. Don't know how much the tickets cost though. They differ from what I seen when I visited the website.
Terms & conditions: This voucher is valid for one free admission when one of equal or greater value is purchased at any Dungeon.This offer is valid until 30/06/08.
This offer is not valid in conjunction with any other offer, promotion or voucher.This voucher has no cash value.This voucher is non-refundable and non-exchangeable.
Photocopies are not accepted. Only one voucher per transaction permitted.The Dungeons reserve the right to alter, close or remove details/exhibits without prior notice
for technical, operational or other reasons, and that no refunds can be given in these circumstances.The Dungeon is not suitable for people of a nervous disposition or
very young children (entry is at the discretion of the parent/guardian). Children must be accompanied by an adult. The Dungeons reserve the right to refuse entry
without explanation. Not valid for fast-track admission.