Our 2L diesel Mondeo Zetec Estate (2006) is a fantastic towcar. It's never been a problem. It was a high mileage, one company, one woman driver, car - which had been meticulously serviced by Ford and came with a full service history when we bought it. Everything had been replaced before it could go wrong, and it was immaculate inside. (It isn't now, unfortunately!).
We use the A75, towing our caravan, through France four times every year, and other people have complained that their cars are underpowered for the hills. We've sailed up (and down) them without problems at all. Not only that but they're cheap as chips (sometimes!), servicing is not expensive, and Ford parts can be bought anywhere - including France should you need anything.
We've had Mondeos - both Estate and Saloon - for years. They were provided as part of our choice of company cars, we always chose another each time we had a replacement, and we chose to stick with one when we bought our own car when OH was made redundant two years ago.
Our caravan has a MTPLM of 1375 - which is lowish by today's standards, but it's a 2000 model and was quite heavy at the time - but it is absolutely no problem for our current Mondeo. The only thing I would say is don't buy the petrol model. We always had diesels, but when our diesel Mondeo was recalled and taken to the Ford factory for investigations they provided us with a petrol replacement and it wasn't anything like as good as a tow car.
We get good fuel consumption too - especially compared to some of the figures I see quoted on here and other forums.