Hi Valerie,
Welcome to PIO's. I also have UK law degree and have completed the BVC but not yet pupillage although this may well be happening now - talk about timing - but anyway in regards to your question about Ozzie law - you need to contact the state in which you wish to practice, their legal admissions board will access your qualifications and indicate what extra study you need to do as far as I know it looks like it is Ozzie Constitutional law which you can do here through the College of Law in the UK (they have a college in Sydney) a bit expensive though if my memory serves me. Each state is slightly different which is why I suggest you contact them directly.
This website might be helpful to you. Haven't read the whole thing myself but see what you think.
http://www.lawcouncil.asn.au/admiss.pdf
Hope this goes some way to answering some of your questions. How does Samuel feel about leaving - my son is nearly 16 just getting ready for his GCSEs which you son will have already completed and was wondering what his thoughts were on it.
If I can be of any further help just send me a PM as am more than happy to help and it will be nice to have another legal person to work through the piles of info relating to this profession - absolute nightmare at times.
Nikci