I'm nit-picking here but the only reason the Herald had a separate chassis-body construction was that Standard were unable to find a pressing plant willing to supply them with a one-piece unitary body. As a consequence the Herald was hugely expensive to manufacture compared to its competitors. There were also problems with getting a water-tight fit between the body and chassis on the earliest version, the Herald 948. This was aggravated by a new-fangled computer-controlled assembly line which I think was one of the first in the country?
As a result Standard-Triumph went bust just one year after the introduction of the Herald and were rescued by Leyland Motors in 1960 who then sorted out all the production issues. Oddly enough the original but problematic Herald 948 is now highly sought after by collectors.