Your post brought a recent escapade of mine to mind. I did 600 mile round trip last year to pick up a new boat, ( this was around 1.2T including trailer ). I had towed such weights before and have since without problems. As mentioned already ensure tire pressures correct and nose weight on caravan should be good, bonus that its twin axle. Anyway the main problem I had was that just as I was arriving in wales, still without trailer, my engine management light started to flicker when accelerating......oh bullocks!! That then progressed to smoking like hell as I didnt have much choice but to pick up the trailer. I had a feeling which turned out to be right, that the crank case PCV filter was choked, it had only been changed 4000 milesish previous but the long run obviously done it in. I had no spare and had to nurse home at slow speed and I was down to 30 on any kind of incline. Its a simple job and if you dont have time to do it before you go, try to pick up a filter before you go and bung it I your toolbox. I carry one in back now as theyre so cheap, I still have no idea if I did my turbo any damage that day but think I got away with it.