The site has been opened in a new window for you to redeem the Thorpe Park voucher codes.
Instructions:People are looking for them and I found these after searching Google. They're valid till October and they don't require you to buy tickets in advance, you're welcome!
I can confirm these do work as I've had friends use them whilst they were with me and there was no issues. They didn't scan them, just took them and applied the deal at the kiosk. Hope this helps!