Keep in mind that the PAL version also includes additional languages. You might say "then why not release an English-only PAL version first?" but that would A. undermine their import block, they'd have to make GCs that only play english or other language PAL games to prevent people from importing from the UK to continental Europe and B. it's more expensive to produce multiple versions of the same game. They have one manufacturing plant for all of Europe, they'd need to produce two versions of every game and thus reduce the output per game. Also, the games couldn't be shipped between regions (e.g. a game sells badly in the UK but is in high demand in Spain, you'd have to scrap a whole lot of copies and produce new ones for Spain). I think the reduced manufacturing cost is also why Australia gets the same discs and Cubes as Europe.