This is a link to an old thread about John Grono and Elizabeth Bristow:
http://www.genealogistsforum.co.uk/f...ighlight=grono
I came to the conclusion that they were not related to my Bristows. Also, the DNA manager of my DNA match (who had the Grono / Bristow couple in their tree) also manages other DNA tests which match to me, and from those it is clear that my shared DNA with that person comes from a different branch of their tree, not the Grono / Bristow one.