Works for existing customers, not a referral code. Seems like they are continuing the trend of MONTH15 codes!
Personal Opinion:
These meals are pretty fantastic. Out of the 22 different meals I've tried only 4 were ones I would not order again. The food is fresh, tasty, and works out to be about $8 each for me when I buy fortnightly. Would highly recommend! I am also entirely unaffiliated with this company.
I followed the link and says you can use code WELCOME20 to get $20 off your first order! Even better. Thanks!