I wonder if that stunt had been set up for other broadcasters too as it seemed like a lot of effort and expense.
I was pondering that, but then Top Gear has a big budget and a few tens of thousands of pounds for ~ 10 of minutes of prime time TV isn’t all that much really. Especially when you consider how much it costs to just film them doing something normal like driving on some roads in Italy (flights for 30+ crew, plus say 60kg excess baggage each, hotels and hire cars for a week, logistics and admin of getting roads closed, camera hire, minicams, ‘talent’ wages, etc). A days crane hire and a steel box isn’t all that much in the scheme of things.
No worse than say building a set for Casualty, then crashing a car into it, and doing that every week.
And a Rover Metro wouldn’t work so well in other markets, so you’d need to have a similarly modified 2CV, 500, Lada, Beetle, etc.