Hi Bob,
I have the family of William Cardwell and Margaret Chambers pretty well documented and have even saw extracts from their family bible. Yes, this family would be a connection but is not the family I am after. It too as you say has a William John. But if this were the man I was after it would have made him quite young to have fathered my Great Grandfather . Also older family members recall Mary Ellen(younger sister of William John born 1839) visiting with them.
It is, as many who are researching their trees find .... that the same christian names run in so many of the families which makes for confusing deciphering of info.
While searching for my Cardwell tree I have come across several different spellings of the surname. One of which is Cardle which is how my own Great Aunt (who was Cardwell by birth) pronounced it.
Also in the Griffiths valuation the family were misrecorded as Carroll (Drummiller Townland).
I Have used the 'ask about ireland 'site to pinpoint their location at this time and have explored the area.

Thanks again Bob for your input.
Aljepeka