Thanks both of you

I think she has only been doing it a year...And she is seeing a therapist but really irregularly so I don't think it's helping much. It's kind of a touchy subject which we don't talk to each other about but we both know I know what she's doing...She's always going to the toilet straight after eating anything and stuff. I don't think she's in denial but in a few days she's moving in to a flat with a few other girls and my parents are worried that she'll start bingeing on all of their food which is what she used to do when she still lived at home with me and my parents and my other sister.
While she was doing her bingeing at home my parents went to such lengths to stop her like padlocking the fridge, locking the kitchen and hiding the key and even redecorating her room so it could accomodate a kitchen of it's own with a fridge and everything so she could buy her own food.
Now that she's moved out they're much happier and get on with her a bit better but they've now made sure that the financial support they're giving her is controlled so that she only gets about £10 a day and she can spend that how she wants ~ they know it'll probably be spent on food which will then be thrown up but there's nothing they can do about it. She does have a job but has only just started and at the moment is not being paid. She's trying to sort that all out so that she has some sort of income...The thing is, this job could be potentially unreliable in terms of stability, meaning that all her efforts and her input to her job could come to nothing and because she's been giving it her all, she'll get depressed and start bingeing even more.
I do give her my support, me and my sisters are all very close but it's not something we talk about directly. I think she's embarrassed by it to be honest. The other day she was at my house and my dad shouted up the stairs to her "you're not throwing up up there are you?" and she got so upset cos everyone heard.
Anyway, i'm sorry that was so long! I have alot to say on the topic
Thanks for your help!
Also, (going slightly off topic :p) missla , melbourne (i think that's where you live right?) is the place I want to live when i'm older! It'd be like a dream come true for me if I could! I love anything to do with australia (i'm seriously obsessed hehe) but melbourne in particular