Thanks guys. I do mean UK codes - the Mario Kart one was from a UK e-bay seller, but the other two are the 'code in a box' type from an online retailer (coolshop).
I think Yoshi9288 is probably (hopefully!) correct, because I've noticed German and Danish e-bay sellers selling download codes on...
I'm British but I live in Thailand, and currently have an American 3DS. At the end of the year I will be moving to Ireland where I plan to replace my American 3DS with a European New 3DS XL.
Recently I have bought some download codes online from UK sellers - Mario Kart, Mario vs Donkey Kong and...