I posted on HUKD but the deal got slammed into oblivion by people on there who don't accept people not might want to wait a month
but in summary buy from the xbox store in the US, works out at £40
XBOX ONE ONLY
Microsoft seems to have decided completely against both cross-regional PayPal and credit card use. Now the only way to buy stuff is with Microsoft Xbox Gift Cards. These are sold in many places but the best way is to go to Amazon.com and buy them there. Below is a direct link to that page.
http://www.amazon.com/Xbox-Gift-Card...dp/B00F4CEHNK/
You need a couple of things to buy from the US Store. Create a vPost account and use that address when adding your credit card to Amazon.com and when adding a billing address on your Xbox. Using that would make sure that the address you use is actually linked to you, even though all the codes will be sent by email (remember to buy "online game code" and not "card"). Remember that you must choose the vPost address as your Amazon.com billing address or you won't be able to buy the codes.
Using the address from vPost lets you buy from the US Store. Since it is an Oregon address you will not have any added sales tax.
With these things in hand, follow these instructions:1.On your Xbox One go to Settings>System>Language & Location and change your Location to United States and press reboot.
2.Go to Settings>Payment & Billing>Change/Add billing address
3.Enter your name and the address provided by vPost
4.Redeem your codes from Amazon
5.Buy stuff
6. (Optional) Change back region to whatever it was before, don't worry, you can change as often as you want and your billing info is saved for the next time you want to switch to the US Store and buy something.