Yes they do. Credit notes are valid for 12 months from the date and time of issue. If you have not used it within 12 months, the balance will be cancelled.
The value of your credit note is displayed on the voucher, or can be checked in any New Look store.
You cannot use credit notes for online purchases, however any New Look store can place an order for you using the credit note funds as payment.
Credit note funds do not need to be used in full if a purchase cost is below the available funds. Each time a credit note is used a new credit note is issued with any remaining funds and a new 12 month expiry period will begin.