Pretty much any 1.9 tdi/dci should do the job with ease. I currently have a laguna estate tdi low miles & history for sale. Tow bar fitted. An excellent tow car.
I agree with Grampian, the dual mass flywheels are a big issue cost wise. We managed to avoid these with our three Mondeos. Richard nicked my Mondeo when his job meant a lot of high mileage driving.
We towed with all three Mondeos without problem, inc
Ding a fairly heavy folding camper. It was an ancient pressed steel, hard top, which weights a fair bit.
You will laugh but we are on our second X Trail and it is not expensive to run at all apart from fuel costs. I paid £2800 a year ago on a 52 plate. Drives like a car, very comfortable.