Instructions:Just been e-mailed this voucher, doesn't say new customers only anywhere so guess anyone can use it, although you can only use the code once per account.
*Promotional offers: Each promotional code may only be used once and is subject to a minimum order value of £30 and to account status.
Returned goods, financial services products and delivery charges will not count towards the value of the order. This offer cannot be used in conjunction with any other discount or promotional offer. These codes are non-transferable so may only be used by the person to whom they are issued and must only be used in accordance with their terms and conditions of use.
As always with Great Universal though it could be temperamental so sorry if it doesnt work for you!