Refund by bank credit instead of gift card

detroy Post #5:

The trader must give the refund using the same means of payment as the consumer used to pay for the digital content, unless the consumer expressly agrees otherwise

I'm wondering if the op may be misunderstanding the above and believes he can dictate the refund method, which it obvious doesn't.

Wouldn’t make since for curry’s to refund you any other way, they sold the vouchers at a heavily discounted rate to a 3rd party who then after taking there admin and profits sold them onto you at a discounted rate.
Refunding you £752 for a voucher that they sold for approx £600 or so to the 3rd party, you be better taking the voucher and selling it privately to recoup the cash