If you're going to look at UK specifications (which I don't consider relevant, but some do) make sure you notice that the tongue weight
rating is well under 10% of the trailer weight
rating. That's normal for European caravans, an accommodation for the smaller vehicles that are the norm. It works over there because towing speeds are lower and newer vehicles come with anti-sway software that most vehicles lack over here. In short, there's a lot that's different, including vehicles, trailers, highways, and towing laws.
As far as I know CanAm is the only North American dealer that will outfit a vehicle to tow based on EU specs rather than NA specs. And it isn't cheap. For what it would cost (including travel) to have them set up your Focus to tow a trailer when Ford says you shouldn't, you could probably upgrade to a vehicle with a suitable North American tow rating. Assuming you like Fords, a used Escape
V6 or Ecoboost4 is easy to find and not too expensive.