Have just been through an audit and this was raised. I had to demonstrate that the land purchase was for investment.
just be aware some expense go to your cost base (plan's / architects fees / etc) that will be deducted from the sell price, not during holding.
i had also put in my back pocket a rental appraisal for the building and also had a set of plans drawn up too where on the plans it said "rental property at xyz for NathanK".
you just need to demonstrate you had the intention to rent it for investment, not for yourself.