I found that the application process for UK business schools to be about the same as that of US business schools. Each will have a certain criteria for acceptance that will take into account your career progression to date, undergraduate record, GMAT score, and personal interview.
In my personal experience, I found that doing an MBA in the UK was far different from my undergraduate experience in the US. I felt that my undergrad was more rigorous and challenged me to think, while the MBA was more answering exam questions with the professor's preferred method or solution.
I've just begun a new job in the financial services industry after having spent my entire pre-MBA career in consulting. While the MBA allowed me to reach my goal of career-changing, I feel that by doing it in the UK, I have made it more difficult to return to the US, without taking a position that is either below my current management level or salary. I did apply to a number of top-tier firms in the US, being ignored by those that recruit from select MBA programs only, and making it to a number of final round interviews and assessment centers with the rest. In every interview I had in the US, my reasons for going to the UK were always challenged. And when I would respond that I came here for international colleagues and experience, they would respond that their program (Wharton, Kellogg, MIT, HBS, etc.) was also very international and higher ranked. Needless to say, I focused my career search in the UK and EU after running into this a few times back in the States.
It's good to hear that you do have a friends and family support group over here. It really will makes things much easier. During my MBA interview, the dean of administration explained to me that of the students that come over with their partners, half end up breaking up or divorcing during the course. And while my first reaction was that this was a bit of an exaggeration, the reality with my class was not too far off. Over a third of the co-habitating, engaged and married couples in the program split up. About half of these people did end up dating someone else in the program, if that's any consolation. Maybe it's not different than what may happen with people at work, but I've never come across it before so I may be overly sensitive to this issue.
At any rate, I wish you all the best with your studies. The MBA is a really great experience and I'm glad that I was finally able to do it.