John Edwards, Barrack master of Dunmore

Hello Everyone. I am looking for information about John Edwards, formerly a Major in the 75th Regiment, British Army who sold his commision around 1793. He was born about 1743, I think in Ireland but I do not know where exactly. He married Mary Bunn who was previously married to the painter John Opie. There was a huge divorce scandal with Opie procuring a divorce in the Houses of Parliament in 1795 after John Edwards and Mary ran off together. They are said to have married shortly after, but no record has been found. John was Barrack Master at Dunmore from 1804-1818. He died in Tuam in 1818. I found his death on rootsireland and I managed to locate a grave inscription on IGP. I am not sure what happened to Mary in the years after his death. She is found at North Lodge, Kilgobbin in 1831 where she wrote her will. She died in 1832 but I have found not record of her death. In the will she mentions her daughter "Mrs Maria Brown of Swainswick near Bath.' I havent been able to find a birth record for a suitable Maria Edwards and I have come up with nothing in Swainswick. I am not sure Maria is John Edwards' daughter as Mary was said to have had two illegitimate children prior to marrying Opie. I hope somebody may be able to help.