Douglas was born in the Sculcoates area of Hull. His parents were Harold Ernest Long and Annie E Farnell. They married in December quarter of 1914 in Sculcoates. Harold Ernest was born Sept quarter 1891 in Sculcoates son of John Long and Hannah Tall. John was born c.1826 in Gatesforth, W Yorkshire. Hannah was born c.1850 they married Dec quarter 1876 in Hull.
Annie Farnell was born c. 1894 in Hull she was the daughter of George and Annie Farnell.
So far that's all I have found hope this helps. I have found them on the 1911 census and can copy the image for you if you would like them?
Its funny my fathers middle name is Douglas, his father was Harold. They say names run in families so even though mine are from Warwickshire
There were two other children siblings to Alfred, Renee G Long born September quarter 1921 and Thomas B Long born March quarter 1926. Their parents were Bertram Long and Gertrude L Jeffery married December quarter 1919 in Hull.
I will search the 1911 census for both of your grandparents if this is the correct family?