Buy a bottle of Volvic Disney themed Star Wars or Frozen mineral water from Asda in-store and claim the full amount cashback from CheckoutSmart.
TIP: The app says to check the front of the store in the chiller - basically, wherever the chiller is that has the drinks with the grab-and-go sandwiches and snacks etc.
Running from 13th Dec until 11pm/midnight of 14th December (thereabouts). Check the app for updates on time remaining for the offer tomorrow - make sure you take a photo of your receipt and upload in time.
It's possible not all stores have stock - check in the app for your nearest store that is stocking it.
Read more about CheckoutSmart: https://www.checkoutsmart.com/