Others will hopefully advise also mate but I would personally be looking back a year or two for a low km say 2000-2002 GU TD4.2T wagon for your 20k price range. Our family wagon is 2001 of same and nearing 400,000kms with nothing but basic services :-) Honestly do have mates up FNQ&NT who are still running TD4.2&T donks to near 1,000,000kms well serviced, no BS :-) !