You can complete this several times if you wanted, all you have to do is create temporary emails. Just make sure the staff don't notice you all the time, requesting your free drinks . The app offers you a free hot drink as usual plus a free cold drink when you sign up to Greggs Rewards by downloading the Greggs Rewards App. This offer is only available for new accounts from 17th July until 10th September 2017 so I would download it quick and enjoy the offer
