I guess the biggest question is what is your all up weight of what you're towing. Remember, be realistic, because if there's an accident, the insurance company will definately be checking.
Personally, I reckon I'd be looking at an "SUV" style of vehicle and if TDi, I'd demand it be automatic tranny..... and my #1 pick for a balance of reliability and quality would be a SanteFe. I know someone who has a few as company vehicles, is on their second batch, and have never once had an issue. 2 tonne capacity too, so it has a bit up its sleeve.
Haggle on something like this or buy a private one;
http://www.carsales.com.au/dealer/details/hyundai-santa-fe-2007-12199428?base=1216&vertical=Car&Range=Price:Min,25000~1&eapi=2&sort=default&cr=0&__N=1246 1247 1252 1282 1216&silo=Stock&find=diesel hyundai AWD|CarAll
A diesel Grand Vitara would go close, but I can't remember if they were available as an auto. Something like this;
http://www.carsales.com.au/dealer/details/suzuki-grand-vitara-2009-12144469?base=1216&vertical=Car&Range=Price:Min,25000~1|Year:2008,Max&eapi=2&sort=default&cr=0&__N=1246 1247 1252 1282 1216&silo=Stock&find=diesel vitara |CarAll
X-Trails and Captivas are ghay.... can't tow squat.
And, FWIW, I would avoid euro like the plague. Especially a DSG equiped euro. I love the way they drive and "feel", but they're not a wise 2nd hand "out of warranty" purchase in my opinion.