Welcome to the forum Malcolm. You have to look at the GVM (about 1550kg) of the caravan and start with a towing vehicle that has a tare more than the GVM of the caravan.
With the high level of torque in the modern diesels one need not frame the engine size as at least 2.8L.
Next you can look at the gear ratios of the vehicle. Some will be running at very low revs at towing speed and if auto box it will constantly shift down. Try to find a vehicle that will rev slightly above the max torque when the speed is 110. Again if auto my choice would be to at least have a sport ratio that can be used for towing. Most vehicle nowadays.
Although some campers will say the more the better personally I would be happy with 350Nm plus as enough. The Audi Q5 is only 2L and has 350Nm and the weight is more than the Classique and should be a capable towing vehicle. The BMW X3 2.0D as well. Further you can't go wrong with a Ranger or Hilux or Fortuner.
I would just stay away from a vehicle with CVT gearbox for towing.
I am sure you will get some lively replies on this topic.
There are times when it is uphill and you have to move the caravan in a tight spot. That is the time that clutches are burnt and the auto is preferred.
Some vehicles are geared for economy by working on low revs. They keep on hunting when you tow and one feels the gear changes all the time. The ideal would be to test drive the different vehicles with a caravan. This means one will have to shop for a 2nd hand model to get the feel before deciding.
Read HERE for a previous chat about tow cars and some campers experience although models of a few years ago.
Edge is spot on with his vehicle of choice :)
Just as Fransie is happy to tow most caravans with less than 300Nm I am also very happy towing 80% of the time in 5th gear and only 260Nm from a 2L engine. My caravan has been loaded up to 1400kg before the weight problem surfaced.
My towing is relaxed and I don't mind loosing speed on an uphill but don't have to change gears all the time. Engine has max torque even at 80 in 5th gear.
Peter can you perhaps send me an e-mail to woonwaled by gmail then com
I have found that these trucks exceed my towing speed on a decline so I would overtake them on the incline where they tend to be slower. It might take time to get past them this way but the towing is part of my camping time - relaxed.