My understanding is that amazon.com is based in the USA ans amazon.co.uk is based in the UK.

I would exoect that the editions they sell originate in the country the site is based. It might be worth e-mailing them. As it is such a big company now (but still hasn't made a profit) it might be possible to specify which edition you would like. There are lots of other web-based book-sellers so it might be worth checking out.

I suspect that the trend towards globalisation might change all that anyway, then we can all read books in their original language. I notice that business titles are often available only in their American editions.

Good luck