- Click here to start
- click "Claim Coupon"
- select "United Kingdom" as your country and fill in the rest of the form
- click "Submit" to see your redemption code
- copy it and redeem it on your Xbox Live account to get the avatar armor
Of note, if you receive a warning from Xbox Live that "this code cannot be redeemed because the item will not fit your avatar's gender", clear your browser's cookies, then fill out the form again. You'll get a new code with, hopefully, the correct gender. (You can use the same email address for each attempt.)