As far as the Grimsby/Lowestoft point, fishing families moved about from time to time - My wife's grandfather was born in Gorleston (Suffolk at that time), his father was skipper of a sailing trawler. In the name of better fishing, they loaded up the trawler with all their belongings and moved lock, stock ans barrel to Grimsby in around 1906. Her grandad and his brothers all became skippers. As far as the lyrics are concerned, I suppose it's relevance depends on whatever area you're singing it in. Sing it in Grimsby and you'll stir up different feelings than you will in Cheam. Two of my wife's family were lost at sea in the name of catching fish. It's that close to home. The one thing I do know, is that I can't imagine fisherman nit-picking about the song like has been going on here!