Hi Brad,
Yes, that is my speculation.
I cannot speak for others in the team, but on the basis of co-incidences of name and location shown through the documents we have explored, it is possible that Mabel SAYLES had relationship with Joseph BROOKS a married man who was possibly by then living apart from his wife, Martha (nee HALL).
He was in the Royal Navy until 1902 according to documents found by Cas and it appears he then moved into furniture sales of some description.
At the baptism of 2 of his children (with Martha) first Doris Martha Florence he was a sailor and by the baptism of John Thomas, 1903, he was a furniture dealer
He was older than the possible mother of your grandfather, Mabel by 15 years or so. Furniture polishing was his occupation at the registration of the boy's birth.
There are details of his whereabouts etc in 1921, but he is not with his wife Martha, as mentioned. Cas has noted he died in 1922.
Albert and Gertrude ROBINSON lived next door to their adopted son, by then known as Joseph BROOKS at the end of the 1930's.
I can use the Personal Message system to let you know what is seen about him in 1921.
Perhaps tomorrow.
Sue