After I had finished my Archi Masters I was working for an architecture firm who also did a small amount of work for a volume builder. They were actually a pretty good quality builder and at least got the orientation of their 'pre-designed' plans correct. We had the ability to make minor changes to every job and it pained me to see so many simple to implement passive options not being incorporated. Had most of their clients known that they would be saving MONEY over the longterm by making a few minor changes to suit their site, they all would have done it. The problem is unless someone can sell this idea to them as a financial/lifestyle choice, many just think it is about saving the world. It is a no-brainer if you have in interest in it, but for those who don't know, there is no-one there selling it to them, especially on the lower end of the market.

Very helpful Off to do more homework . Many thanks

Yes, have seen them used but never used them myself. Worthwhile having a chat with Bellamo and Catt Architects. One of the houses in the link is a Melbourne house designed by them. they'd know the 'in's and out's' of the standards, etc.

Thank you Kate, I will look into the triple walled poly. Sounds perfect. Yes there is fall for drainage. I hadn’t even thought of fans in the corners! It really helps to get another perspective- thank you.