In short, you sure can. See below: 

• Simply enter your gift card number and PIN at checkout and click "Apply" to redeem it - you can use up to 3 gift cards per transaction.
• Take care entering your PIN - 3 incorrect attempts will freeze the card for 8 hours.
• The remaining balance will prompt you to enter your payment card details to complete your purchase. 

Please make sure you keep hold of your gift card in case you wish to make a return. If you no longer have the gift card contact Customer Experience and we’ll be happy to help.

• • If you paid with multiple gift cards: you will be refunded to the first gift card you entered at checkout.
  • If you split your payment between a gift card and personal card, the funds are first returned to your gift card and then to the payment card as outlined in the Terms and Conditions.