I've got a voucher for one free entry when a full priced adult ticket is purchased if that's any good to you. It came from Tescos and can be used for a number of theme parks, of which 'The Flambards Experience' is one (the print is so tiny you need a magnifying glass). it's valid until 31 Oct, can't be used for pre-bookings, and you have to check a website for any date restrictions on using it.
c-a-t me if you're interested.