Oddly this event( around 1870?) is mentioned AFTER the bit about George & Mary, even though it preceded it in timeline
excerpt: "Norman Marten sought permission to marry the widow of John Groat. Griffin remarked that there really was little choice in the matter since “to all intents and purposes [they were] man & wife now, make them so legally, & we secure the Services of an Invaluable man in Norman, for a long time to come for Churchill.”
I looked back into the 1881 just now and saw Eliza ( age 15) & Robina ( says age one, they forgot the next digit as she would be in her teens ) as "Goat", then Agnes as Martin age 11...so all they needed do was consult the 1881 census....