The Sidney E. who married in Durham seems to have moved to London. However, he appears to have been born in 1890 and died 1958 Bromley, Kent. He appears to be the son of a Tom and Elizabeth and was born in Clapham as plain Sidney/Sydney.
The Sidney Edgar of the thread referred to is a different person and bc.1865 - he did himself have a son name Sidney but was a Sidney Henry.
Do you have the 1920's birth certificate? Are you sure her father was named Sidney Edgar Hayman?
Annette