His name is spelt variously as "Allonby" and "Allenby".

Susan Carlisle has submitted the following:

Allenby was the son of James Sisterson and Jean Rogerson of Alnwick.

James was the brother of the Robert Sisterson remembered at Glanton on G4.02 and Whittingham on W48.01. Robert died of wounds at the Somme on 31 Dec 1917 while serving with the Royal Naval Division.

Another brother William is remembered at Ingram on I3.02. His story is told on page 122 of ‘Reflections – The Breamish Valley and Ingram’ by Sarah Wilson. After demobilisation he walked home from Alnwick, got a blister and died of blood poisoning on 26 Oct 1919.

James himself spent WW1 as a motor mechanic with the Army Service Corps and is listed on the Branton memorial now at Glanton G4.02

So the Sistersons are well represented on the war memorials.

John William Allenby Sisterson is remembered at Alnwick on A11.01 and A11.15
Is he the "William Sisterson" listed in Powburn on P39.01?

The CWGC entry for Gunner Sisterson
The CWGC entry for Able Seaman Sisterson