I found a man named Terence English living in the townland of Carrickallan, Civil Parish of Louth in an Irish property record called Griffiths Valuation. Griffiths Valuation was enumerated in the 32 counties of Ireland between 1847 and 1864. The Griffiths enumeration for County Louth took place in 1854.
The entry for Terence shows that he leased a house, outbuildings and two separate parcels of land from a man named James Dulaghan in Carrickallan. Terence had leased one parcel of land which was a little over four acres. He also lease what appears to be another contiguous piece of land a little over 7 acres in size. Griffiths states the value of the four acre parcel was 2 Pounds and 15 Shillings, while the second parcel of land was worth 4 Pounds, 10 Shillings. The house and outbuildings Terence leased were attached to this larger, 7 acre parcel. The house and outbuildings were worth 15 Shillings.
Griffiths, unlike a census, only lists the head of the household and not entire familes the way a census does. In your message to the GenForum you didn't mention if Terence had married Mary Duffy in Ireland or England, nor gave the country of birth for their older children. But, if the family were living in Louth during 1854 this Griffiths entry could pertain to your ancestor Terence English. If their oldest child Patrick was born in England, then this Griffiths entry most likely would refer to another Terence English not in your direct line.
A book by Brian Mitchell called "A Guide To Irish Parish Registers" shows that the Catholic Church in the Civil Parish of Louth (where the townland of Carrickallan was located) has registers that go back to the year 1833. These parish registers would have commenced too late to have recorded Terence English's baptism, but you'll want to search them for his marriage to Mary Duffy and the baptisms of any children he had in County Louth.
You can write to the Catholic parish priest for the Louth Village area of the county and have him search the parish registers for any information concerming the family of Terence and Mary Duffy English.
If you write to the parish priest explian that you believe your ancestors had lived in the townland of Carrickallan. Contact information for the parish priest follows:
Very Rev Seán Quinn, Parish Priest Parochial House, Louth Village, Dundalk, Co Louth, Ireland