Thanks Frances - it is a bit of a teaser isnt it! William is a name which appears in my family and a marriage in 1775 could have resulted in a son the right age for the John I am looking for. Oh for more information - is there anyone I can contact?
The Whitehaven suggestion very welcome - I knew Corkills went there to the mines, but I hadnt made a possible fishing connection with all three places.
Thanks again and if you can help more with those Corkills in Cornwall, or know someone who can, would be v.grateful for further info.