UK Mturk users - how do you use your amazon.com balance?

I'm new to Mturk - been using it for 2 weeks. As a UK user it seems I have no way of cashing out my earnings to a bank account. Instead I can have my balance in Amazon.com.

Has anybody found a way to convert this balance to anything usable in the UK? Cash is my preference, but even vouchers that I can use on something (including Amazon.co.uk purchases) wouldn't be too bad.

Any solutions would be helpful. Thanks.