I am interested in this Yorkshire connection. From what I understand of my own family lore (sadly anybody in my close family who'd really know are now dead) I come from a family of Newmarches who were timber merchants in Beverley, Yorkshire.
Family myth is that a Compte de Neuf Marche came over to Britain with the Conqueror in 1066 and was given estates in the North of England. There is another exotic link to George Duke of Clarence (he who was drowned in the butt of Malmesy wine in Shakespeare's play) who apparently fathered a bastard on one of the Newmarch girls from whom my line are all descended. I take all this with a pinch of salt.
The Newmarches were, however, leaders in the timber trade in Beverley in the 19th Century, with a splendid house which I think I have identified. (There is only one house in present Beverley which straddles one of the gates of the city; it's now full of law offices, but the "over the gate" mansion is very much part of our mythology).
One of the Newmarch sons, a railway engineer, came out to North China in the 1890s to build the Peking-Mukden railway, China's first. He had an Irish wife who was reputedly "rather grand". I don't know their names but could probably find out. Their son, Guy (another railway engineer; he designed most of the railway bridges in Manchuria) married the daughter of some missionaries called Catherine Muir. Their daughter, Anne Newmarch, was my mother.
Guy Newmarch, my grandfather, was caught in the Japanese Invasion of Hong Kong in 1941 and did not mentally survive the ensuing incarceration in a concentration camp very well. When he came back to London at the end of the war he tried to plant a paddy field in his garden in London's Rupert Square. My grandmother promptly divorced him and he disappeared off to South Africa. The last we heard from him was a congratulatory telegram on my birth in 1953. In the fifties my father tried to search for him but the application was confused with somebody else's enquiry and the upshot was that we got a letter saying that Guy Lumley Biddulph Newmarch had permission to fly a single seater aeroplane over Singapore. All very confusing - but I would like to find out what eventually became of him. Perhaps somebody on this correspondence knows.
If it's any help the family heraldic emblem was a Griffin Half Rampant with the motto Auxilium ab alto.