All contrived to slag off Reliant for cheap laughs. We used to watch the programme for the comedy, it became less entertaining when those presenters moved on.
Any three wheeler, and some 4 wheeled vehicles would have overturned driven down a slope and turned sharply on that adverse camber, especially when loaded with the concrete you could see, and the concrete in the back.
Reliant engine was an Aluminium Block update of the original Austin 7, so the myth goes. I found them to be smooth and quiet, economical and reasonably lively. At the time it filled a niche market and was cheap reliable transport.
Swarfy.