We aim to make this process as simple as possible, however each voucher code will have different T&Cs as to when this can be used. These should be featured on the marketing communication you were sent or a link to the site will be provided where you can find the details about that specific voucher code.
If your voucher code is not applying for any reason please contact our customer service team by clicking here and please include a screenshot of the voucher code so we can look into this straight away for you.