Have a look at Mercedes C or E class 220 cdi diesels. The more recent versions have good BHP and torque figures 170 bhp and 400Nm which are actually better than the previous ML270 4x4, lower in tax and insurance and should give very much better mpg solo. Towing weight limit is 2000kg. snag is that ball weight is only 75kg which may take some careful loading to achieve.
The BMW 2 litre diesels in 3 and 5 series are of the same order.
I would have a look at the data plate on your Hobby as most of them I've seen have been somewhat above 1400kg.
You may also have some trouble getting to the "suggested" weight ratio with this sort of caravan and standard saloon car but if you are an expereinced tower this may not be out of the question.