Andy,
We have a Elddis Avante 524, (2006 model but `new` this year), 1350 kgs, towed with a WV Passat 140TDI Sport Estate.
Tows well, easy 60+ cruise, (boot full!), 28mpg towing.
I do need to drop to 5th to maintain 60 up Windy Hill (M62, J21-22), and the long climb south of Bristol on the M5, otherwise is just goes. It`s a manual, don`t know if an auto would be going down the box, but if doesn`t drop revs I usually leave it to the torque to do the job.