Hi Adam,
Well you know about sleeping with... and I put a reply there with another Hostel for you, and also bumped into a girl down in Melbourne who was heading back to Sydney and was going to stay at The Big H again seeing she reckoned it was pretty good - it's in BUG too as is Glebe and YHA Glebe but both a little further from CBD, 10 min. bus ride, but they would be next on the list.
You're planning a fair way ahead and if you haven't hostelled before, just go visit somewhere else over there for a weekend or few days and see what it's all about - great environment to meet people from different countries - and you'll possibly be able to help out some people from overseas visiting UK, who knows, maybe meet some people also heading downunder next year or make some travelling contacts anyway.
But what will you be in for - a great time, sand, surf, sunshine, chicks in bikinis, cold beer, football played the aussie way and not just rugby or league but the real stuff - AFL.
As a chef you'll be able to get work just about anywhere and if you're starting to like it down here, think of doing your three months regional work to get a second WHV - doesn't need to be the hard yakka doing fruit picking, for there's
www.wwoof.com.au where you can do about 20 - 25 hours farm type work in return for food and accomodation, and as a chef doing that in a country town area, you could probably pick up work at some local pub as well.
If you're planning to stay in Sydney until NY, think of making a booking (seven days minimum usually Xmas to NY)( just in case you ain't in with the sleeping mob or somewhere else) about May/June as bookings will fill up near as soon as they are open.
Also, getting yourself settled somewhere for the first six months is not such a bad idea either if you want to pay a lot less tax as you can get yourself classed as a resident for taxation purposes and pay a damm side less tax - all details on
www.ato.gov.au and April is just about the right time to consider heading up the coast to the top end (getting your three months in as you go, and it does not all need to be in the same place.
Once you have the second, and you like it down here and maybe you want to stay, then you can always look at putting in a permanent residency visa application while you are in Oz.