And also, height would also
> depend on a number of things such as country, relative
> wealth of country, economic station, etc. In other words,
> on the average, an undernourished waif from the gutters of
> London will likely turn out to be shorter than a farm hand.

Indeed so, though farm hands weren't that well fed. Among the wel-fed gentry of JA's class the height would be much the same as it is now, but most people were not well fed.

A hundred years later (sorry, I forget the source for this), when conscription for the First World War came in Britain, half the men called up were rejected as unfit for active duty - and this was a time when the authorities weren't very picky, and the men were in the prime of life. This is one reason why the ANZACs got such a reputation - they were several inches taller than their British cousins.