Good luck with your application.
I would try some other airline first. bmi has been going down hill for years. Like most big airlines they make big decsions quickly and then spend years in denial with demoralised crew and larger cost implications.
I was flight deck for bmi and my wife was a Flight Supervisor so I know a few stories about bmi and their management. They don't reward loyalty and you certainly won't have a life whist working for them.
The bmi baby cabin crew manager at EMA told my wife off for smiling and being nice to passengers!
I don't know where they get them from!
Cabin crew is a thankless job but it would be a good experience for a few years, but not realy a career.