Windows 8.1 preview and English UK

I'm currently use Windows 8, in English UK. The preview will only be available in English US (not UK), and you can only upgrade via the Store and keep more than just accounts if you're using a language that the preview supports. I was wondering if the slight difference in language means that I'll have to use an ISO and basically clean install, or whether people think that an upgrade will be allowed.

It seems crazy to think that minor region differences result in a different upgrade experience. If Microsoft keeps doing annual updates, with previews not supporting English UK, I may just stick with US English, even though it's full of "z"s in the wrong places (for me) and it wants to correct "favourite" to "favorite" all of the time.

What do you think - will they allow an upgrade? Or will people in the UK have to use an ISO and lose the upgrade experience? I guess I'll find out on Wednesday, but I'd rather have time to know and switch over to US English now if necessary.