In 1909, Lady Elizabeth Cust wrote in "The Records of the Cust Family Series II - The Brownlows of Belton" that "Another branch of the Brownlows of Nottinghamshire settled in Ireland early in the seventeenth century, which is now represented by Lord Lurgan. The Brownlows of Lurgan always believed themselves to be related to the Brownlows of Belton near Grantham and for many years carried the same arms and crest. In 1839, when a peerage was granted to Mr. Charles Brownlow of Lurgan, it being found impossible to prove his right to bear these arms, the Heralds only granted him the old Brownlow coat with a difference in the field, viz,. Per pale Or and Agent, as escutcheon within an orle of martlets sable.
"This Irish branch can be traced back to John of Epworth and Nottingham who was possibly a son of John, Mayor of Nottingham several times between 1567 and 1590. Be this as it may, young John Brownlow was married at St Mary's, Nottingham, by Archdeacon Welles on April 30th 1598 to Douglas, daughter of Thomas Roper of Heanor, co. Derby."
According to records at the Public Records Office of Northern Ireland: "Under the Plantation of Ulster, John Brownlow of Nottingham offered himself as an undertaker of land in ONeilland, Co. Armagh. (Brownlow stated Nottingham as his place of origin, his family's native city and where his father had served as Mayor; but he himself had actually been living in Epworth, Lincolnshire, and had only returned to Nottingham on his father's death to claim his inheritance.)"
According to the records of Rev. John Brownlow in 1853, Richard of Belton (Chief Prothonotary to the Court of Common Pleas) was the son of John Brownlowe of Nottingham who was mayor of Nottingham in 1567, 68, 75, 82 & 89) and married twice to Jane Panell and Douglas Roper.
Looking at the evidence above, it is possible that Richard of Belton and John of Lurgan were brothers (but possibly with different mothers).