There are 2 people with him on their trees on
GenesReunited on this link - not sure if you can see that without being member there
And his CWGC grave has
Name: SEWELL, SIDNEY DAVIES
Initials: S D
Nationality: United Kingdom
Rank: Major
Regiment/Service: Royal Engineers
Unit Text: 3rd Field Coy.
Age: 40
Date of Death: 18/02/1915
Additional information: Son of Col. Thomas Davies Sewell and Elizabeth Sophia Sewell.
Casualty Type: Commonwealth War Dead
Grave/Memorial Reference: II. E. 4.
Cemetery: YPRES TOWN CEMETERY EXTENSION