The image I have is 'dated' 1928. There is no evidence to support the date, and yes, in the Blyth book it is dated circa 1920. So lots of room for maneuvering. More research needed.
I am still curious about William Laird of Blyth. He and his wife were both born Scotland.
1891 census age 34, he was living with his family at 12 Crofton Terrace, Blyth. His occupation was Miner, and his family consisted of wife Mary age 27, daughter Janet age 9, Elizabeth age 6, Charles age 4 and Margaret age 1.
1901 census of the same family gives the following information, living at 9 Richard Street, Cowpen, William age 43 and a General Dealer (Shop) which I think is possibly the shop on Bowes Street. His wife Mary age 37, Elizabeth age 16, Margaret age 11, William age 8, Alexander age 5, John age 2 and a one month old baby.
If the above William and your Alex senior were brothers, that might be how the shop was established in 1890. Perhaps something happened that brought Alex back from the sea to keep the shop and it's businesses going. Speculation I know, but plausible, and in need of further investigation. I hope your research provides answers. Please keep us informed.
P