Hi Kagsy. The Perrys I am interested in would be Church of Ireland.
My great grandfather, Nicholas Wilson, married an Elizabeth Perry in Dublin in 1893. The most likely Elizabeth Perry I have been able to find was born in Kiltegan in 1865. This makes sense to me as the Wilsons were located in Baltinglass.
Her father was a Thomas Perry, occupation Farmer. Griffiths Valuation shows a Thomas Perry in Ballinasilloge, Parish of Hacketstown. I notice there is also a John and a William Perry in Ballymaghroe, Hacketstown. I guess that is your William.
There are also wills and probate records for two Thomas Perrys in Kiltegan, dated 1821 and and 1824. The Church of Ireland Cemetary in Hacketstown has a gravestone erected by Thomas Perry of Buile in memory of his son John who departed this life on the 24th of September 1805 aged 19.