Once you received your 50% OFF Unique Code from Wowcher/ Living Social or Groupon.
Go to https://hamperuk.com/collections/all
Add to Cart any hamper you want, fill in your shipping details.
Before Check out you will have to enter your "Unique Code" on Discount Code (as shown below) to get 50% OFF your order, the total amount will be updated and you pay the difference.
You can also refer more information on discount codes here.