The History of The Jago's

I would like to thank both Peter and Stella for answering this question, The conclusion was that this was probably because of work in the big cities. Also many Jago's were Doctors onboard ships or other work mates and went to more industrialised parts of the UK and the world.

My great (x3) grandfather became an Officer of Excise, and one of his brothers became a Coastguard.

my great granddad left for a better life in NZ.

The main industries of  Cornwall involved either the sea or mining. Many Jago's would have been seamen, so you find little pockets of Jago's in the ports of the UK e.g London,Bristol, Portsmouth, Newcastle upon Tyne etc.  Miners would have gone to Wales to become coal miners or to USA ,Australia and other places for gold (amongst other precious metals and minerals)mining. Hope this helps.