Mathew And Isabela Hagan

My maternal great grandparents. Mathew Hagan was nicknamed matha. He was a coalminer like his son. Isabela Jane Hagan (formerly)  Hedley. They are pictured with two boys, one of whom must be my grandfather. I have taken this information from my grandfather's birth certificate and noticed that Hagan is spelt with one "G". All current Haggans have two Gs.