I'm not sure if you're still watching this thread as this response is a tad late. You'll find all the info on the website
https://www.border.gov.au/Trav/Visa-1/417-
So when a young person applies to go to the UK, it's called a Youth Mobility visa but if it's the other way round (British citizen going to Australia) then it's called a Working Holiday Visa. I'm not sure how much the rules have changed but my partner was on one a few years back.
I think the criteria for applying includes having evidence of sufficient funds to support herself ($5000). I'm not sure about having a health assessment done, the website was a little vague about that and my partner didn't have to get one done.
Unfortunately Aussies aren't as generous as the Brits because the Working Holiday Visa has more restrictions than Youth Mobility. Firstly she will only be able to work up to 6 months per employer unless she finds work in one these industries and applies to get permission to work for up to 12 months -
https://www.border.gov.au/Trav/Work/Emp ... e-employer
This is severely going to limit her work opportunities but there's still jobs out there. If she wants to work in a pub then she will need to get her RSA certificate first (Responsible Service of Alcohol) which she can do pretty easily by signing up to a course, it's just a few hours and a multiple question quiz.
By default the Working Holiday visa is one year, if she wants to extend to a second year then she needs to complete 3 months "specified work" - most people do farm work. She will need to start early if she is planning to stay her second year because farm work can be seasonal so most farmers will sign off on a per day basis and from memory I think you need 88 days of work signed off on the form which can take a lot longer than 3 months.
Also might be a little random but useful to know Australia and the UK do have a reciprocal health agreement but it's not like the NHS. She will need to sign up to a medicare card. Chances are if she needs to see a doctor, she will have to pay. So there are places called "bulk billing centres" which means that the patient doesn't have to pay anything but these are a rarity. The majority of doctors requite a co-payment so usually what happens is you pay the full bill and then medicare refunds a portion - a few years back it was $36 but I think they might cover a bit more though but private doctors can charge $100 or so, even after the medicare rebate, it's a lot out of pocket.
http://www.humanservices.gov.au/custome ... -australia
Hope any of this helps!