Thanks Marion. I had seen this already on Family Search but I doubt that it is our John Senior. The Pollock side of my family are very Scottish in their orientation. Our Mary was born in 1833, so Irish John here would have been significantly younger, and Irish Mary is Taggart, not McTaggart. I know that is not necessarily fatal to our search but it was a cross against the likelihood in my view. I have also tried McTaggert, Taggert, Tagert, Tagart etc, all to no avail. Thanks again for your help. I will find him eventually with luck and support from the mighty wikitree.