Thank you for your reply, I have updated news since last posting! I did send for Thomas Coyle's birth certificate and received it! It also gave some unexpected news on it, it gave his grandmother Anne Coyle as registering the birth, this was great as I hadn't expected it.
I was also contacted from a local historian in Castle Pollard who gave me a younger sister to Thomas, Ann Coyle born in 1862 (before registration).
I now have my great-grandparents as Philip Coyle and Anne Cleary, their children, Ann (1862), Thomas (1864), Patrick (1867), Edward and John (1869), James my grandfather (1870), Maria (1871), Philip (1874), Matthew (1876), Ellen (1879), Margaret (1881), and Elizia (1884). - Such a large family!
I have found that John was a priest and Margaret a nun!
But after receiving the birth certificate of Thomas I now know that my great-great-great grandmother was Anne Coyle.
I have been told that my great-great grandmother Anne Cleary may have originated from the Mullingar area too.