Thanks for the reply Terryw. In response to your points:

I believe we are CGT exempt for two years from the date probate went through and we obtained the property. Thanks for the tip on both of us moving in and not affecting the CGT status for up to six years, I already live in there and have done for the past six months but I'll let my sister know and we can organise it that way if we do end up renting it out..

My father will pay CGT on sale of the block, not sure on the stamp suty side of things though. The plan was he would just sell it in his name, pay the duties/tax and then give us the money, saving him paying duties and then us. We were also thinking about doing the building and selling in my fathers name too to once again hopefully skip the double duty. Would probably also try and get him to make it his PPOR for a while before sale to try and obtain the reduced CGT. Not sure if all this is possible however, so I need to look into it more..

I understand there would be difficulties with my sister and I owning investment properties together. However as we are both pretty much on the same page and have similar goals in mind, I'd figured the positives would out weigh the negatives. As we're just looking into our options and don't plan to do anything in the immediate future, we've got time to more thoroughly explore our options and work out if it is the right way for us to go…

Cheers and thanks again for your advice mate