It's obvious, there's clear signs this relationship will end.
She's in a very different environment there. Granted it may not be as convenient or even easily adaptable for her in UK, but it's a completely different world. For anyone young, it's vastly more interesting to explore.
The point is, being in a different setting, her perception, believes are also changing, anything from superficial things like food, clothing, to more important ones, such as life, marriage, career, and lifestyle. If your relationship with her is sound, and you're really someone special to her, she will come back eventually, if not, there's no hope in waiting for her. Regardless of which, for the time being, she's completely immersed in exploring and experiencing her new environment, and going back to the past has little appeal to her. Reality can be tough to accept sometimes.
On a side note, I recommend YOU do the same as well, if you have the means and opportunity to do so. It will open your eyes, and maybe you can better understand why she's changed. And maybe by the time you're through with it, everything you're worrying about may seem trivial.