Hi Bas,

Have reno'd two properties and built another two in Vic and well underway with planning a subdivide and build in Vic.

If you have the time, obviously you will learn more and make more money if you manage your sub division yourself, rather than paying experts.

Secondly if you want to invest the time, learn and hence maximise the money you make, rather than maximising the amount you pay to others you will probably find that you only need a good draftsperson, a good surveyor and a good builder to succeed.
And you'll need to ask lots of questions of the local council. If you are not sure about what any of them say, double check with one of the others. Sometimes draftspeople are little impractical in what they draw, and sometimes council are overly cautious in what they advise etc.

If you have recently been through building another property you'll be getting familar with dealing with council and hopefully have a some or all of these key people already in place. If you don't then perhaps you might be best to tackle something a little less challenging first time round… lower risk, takes less time, but will hopefully yield a good relationship with builder, draftsperson etc. The you can move onto more ambitous projects.

Also many surveyors (and draftspeople) do handle the council planning permit process.

Get yourself a copy of ResCode clauses 55 and 56, which are basically the state wide rules that the council and draftsperson need to follow, and read them. It covers garage sizes and myriad other issues such as overlooking etc.

Best of luck with it : )