I now have more information on this family and have found 5 children for Robert LYONS of Drumnakilly (Killyclogher is a different man).
Robert LYONS married Mary (Johnston or Houston) before 1840.
Their children:
1. James c 1840. Married Isabella Caldwell 22 Mar 1866 in 1st Presbyterian church, Omagh - died 1878 aged 39.
2. Robert
3. Letitia c 1844. Married Joseph McIvor of Bracky in 1859 (he was born c 1834 son of Daniel -not David as listed on the certificate)
4. Andrew 29 Dec 1849 and buried Drumnakilly in 1869 (and buried with his parents- which is how i found them)
5. Mary 16 Nov 1850 Edenderry. Married Alexander Smyth of Copney.
The last two children had records but the mother's surname is listed as both 'Houston' and 'Johnstone' - my question is to Gaffy - would there be an original record and could it be looked at or photographed by someone who lives close to the record centre? You seemed to have looked at an original record for the Mary and Alexander's youngest son Andrew (and so proved that was his name and not Alexander).
I would love to know Mary's maiden name.
Unfortunately the birth dates of the three eldest children and the marriage date of Robert and Mary is unlikely to be found because all those records seem to be gone.
Thanks for your help.