Once they send you the voucher you’ll need to redeem it on a Red Spotted Hanky account and book before the end of June 2014. As tickets are often available 12 weeks ahead, that means you can use it to travel until mid September. It’ll take 72 hours for the code to be activated on your account once you’ve entered it.
Remember to check our 10 Tricks For Cheap Train Travel article for other money saving ideas.
Be quick as I’m sure they’ll be popular.