I have just found your very interesting post on the Ancestry message board re Hendrie Twatt and believe I am descended from him, through my mother's family, (Thwaites).
Her grandfather, Captain James Charles Thwaites, was born in Shetland on 21.11.1854. His parents were Charles Twatt and Mary Twatt. I know very little of Charles Twatt but Mary was the daughter of James Twatt (born 1794, Sandness) and Grace Robertson.
By the time of the 1861 Census, Mary and her son James Charles were living in Sunderland, County Durham. Mary was a live-in servant, and her son, James Charles,was living with Mary's sister, Jemima Calder (nee Twatt) and her husband, Adam Calder (also from Shetland), in Sunderland.It looks as though Mary was a widow by this time.
At some point Twatt became Thwaites.
In later life, Mary lived first with James Charles and his family, and then with her unmarried sister Isabella , who had also moved to Sunderland. James Charles entered the Merchant Navy as a teenager and rose to be Captain. Before he retired, he was a Trinity Pilot escorting merchant ships through the mine fields of the English Channel during the First World War. When he died hin 1936 he was the subject of an obituary in the Sunderland Echo.
If anyone reading this has any information on James Charles's father, Charles Twatt, I would be delighted to receive it.
James Charles and his first wife, Isabella Thompson Olley, had at least 11 children including my grandfather, Stanley William Olley Thwaites.