If you're talking about getting an EU preorder code then you're in luck, this was actually an error on SE's end, not GMG where the 18 digit code was spitting out EU 20 digit codes. It was posted somewhere on their twitter they were aware of the error (my friend bought her copy from GMG and had the same problem), I'd advise just trying it again since according to the same friend she put the 18 digit code in again last night and it gave her the proper code.
If this isn't what you're referring to then sorry for the inaccurate response!
If this isn't what you're referring to then sorry for the inaccurate response!