I looked at the 1849 Griffiths Valuation head of household listing for Co. Kilkenny. There were no English records in Thomastown or Pilltown. There was a William English in the town/village of Mooncoin living on Convent St. There were 35 people with the surname English in the 1901 census for Co. Kilkenny including ten children under ten.
Have you considered DNA testing?