Yep, nothing in the T&Cs about restrictions on which country you're from, but also nothing about the prize including airfares etc.
Interesting that they're doing it in B+W, considering most of their business would come from C41 / RA4 / E6 chemicals (OK, I know they make Neofin / Ultrafin etc for B+W, but how many people actually use that compared to their colour kits?)
I definitely like how you have to post in a final print rather than scanning it, then you know exactly how it's going to be displayed.