Hi Ade and Roger, I have previously on Ancestry dealt with queries on Callaghans of Templeport, including one family who went to Scotland and then Australia, also was in contact with a lady in Australia who was interested in the Templeport Callaghans, found none there but did see in an old newspaper archive reference to a lawyer Callaghan of Templeport, year 1899. Search Ancestry under Help and Message Boards, find Cavan etc it is a subscription site but this feature is I think free.
There is a long thread on this site which I entered late but I got no responses personally,
see https://irelandxo.com/ireland/cavan/message-board/callahancallaghanso%E…;
I have done my DNA and was in touch briefly with a gentleman in Sheffield who informed me that an American match to him on the line had told him it was their records or family story said the Callaghans were cattle dealers who came from Cork to Lislea in Fermanagh, now Northern Ireland but very close where they bought or leased land as much as they could, this was 1770 so would be difficult for Catholics to purchsase land. My ancestor was from the parish of Castletara, large gap in church records unfortunately, currently most Callaghans in the area are in the parish of Annagh, all these places are on the border of Cavan and Fermanagh.
There are pieces of the 1821 census for Cavan surviving but do not think Templeport is there.
If Ade wishes to mail me at my site email of stpeters@irelandxo.com I will reply on my personal mail with anything I have but not a lot more.
Good Luck
Pat