Sorry, I've been otherwise occupied for the much of the time lately including all day Tuesday, hence a delay in responding to a post from Jim.

On Monday he said (in response to me)
"you have totally ignored the main bit of my question".

I did not deliberately ignore anything. If I overlooked the main bit please point me to it.

In the same post Jim posed some apparently rhetorical questions
"How many of them worked the land to become familiar with the working terms that appear in the songs, the problems of seasonal changes, the pressure of having to pay rent....?
The same with going to sea or to war
How many of them experienced the family life where it is necesary to preserve your good-looking daughter for suitable marriage in order to try and take a tiny step up the social ladder - how many of them experienced the family conflicts that causes?"

All those things happened to people and all those things got written about, but what we're asking Jim for is evidence from within the songs that the people who made them were the people who had experienced the events, or else people close to them in the same social class.

GUEST,jag cited Shoals of Herring and Jim commented that MacColl based it on the words of Sam Larner. Indeed: a skilled song writer who had not worked on a fishing vessel talked to someone who had and thus acquired the material for a song. Sam himself did not (as far as we know) make a song about it. So we have one person with the experience and a different person who was the song writer. Clearly that is not the only possible scenario but it is a very plausible one for a lot of songs.