Expires 30th April 2012.
Went to WH SMITH today and was given a card saying Free Graze Box. If you go to the deal page and enter code SMITHFREE you will have a free Graze box, including either free nibblebox or nutritiousbox. You will need to provide your credit or debit card but the first box is free including the delivery but any consecutive boxes will be charged. You can cancel anytime as soon as you order your first box if you don't want a subscription.
T&C from the voucher I was given is below:
This offer is for new graze customers only. Valid credit or debit card required but your first box is free & you can stop deliveries at any time. Ts & Cs at graze.com/whsmith