You certainly don't have to go as high as some people think to get a defender 200/300 tdi ute .... or a tdi disco (there was a registered 2 door 300tdi manual at Pt Macquarie recently for $1500).
There are 200/300tdi utes available under $7k (take a look on gumtree Land rover Defender 110 ute | Cars, Vans & Utes | Gumtree Australia Tweed Heads Area - Tweed Heads South | 1030221277), and 1993 Land Rover Defender Ute | Cars, Vans & Utes | Gumtree Australia Bega Valley - Wolumla | 1030152282, even down to $5k, but as others have pointed out, they could be well used and a wise buyer would expect it to need some $s spent on maintenance. But as bluemin pointed out above - it doesn't all have to be spent at once - you can spend it over time.
The major problem may well not be cost but rather whether the one you want will be available at the time that you are ready to buy.

