Hello!
I was extremely lucky and managed to get into BA after my first interview for cabin crew. I think it varies quite a lot though - they explained at our interview that most cabin crew get in after their second or third attempt and it's not that they don't like you if you haven't got in first time but maybe you need more customer service experience, for example!
I know in my case they explained on the day that they score each individual on a points system throughout the day, and if you score above a certain mark you get in, and if you don't, you should try again. They explained to us that they have jobs for everybody as long as you reach their 'target' score!
Hope that helps a bit!!
