Hello afb57
Occupation Road, Belvedere, was one of the main "roads" through the centre of a permanent Romany Gypsy/Traveller encampment. Called the "Belvedere Marsh Romany Encampment" it existed on that site since at least 1900 or so.
The majority of the people living there were Romanies/Travellers but there were also some non-Gypsies. They lived in mixture of vans, tents, wooden sheds and bungalows. There is a book about the community written by someone who was born there in the 1930s and grew up there - Betsy Stanley. It's called "Memories of the Marsh: A Traveller Life in Kent" and is available from the Romany and Traveller Family History Society. It's listed on their Publications page.
As well as being the autobiography of the author, the book includes a map of the "plots" along Occupation Road, plus a list of the names of the people who lived on each plot. "Alford's shop" is in that list. I would suggest that the Alfords lived there on their business premises rather than it being a shop only.
There were moves by the local authorities in the run-up to the Second World War and during it to move the inhabitants of the Encampment so that the land could be turned into allotments and public space. Its final demise was triggered by the dramatic 1953 floods of that area which destroyed many homes in the Encampment and its surroundings as well as loss of life.