Walter has proved very difficult to identify with absolute certainty. The information contained in the source "Soldiers who died in the Great War" is, as always, brief: "Birth Place: Huddersfield ... Residence: Pellou, Yorks" along with regiment, number and date of death as well as place of enlistment.
Margaret Stansfield’s excellent Huddersfield’s Roll of Honour 1914-1922 can offer no more information as to the identity of Walter.
There is no "Pellou, Yorks" but it may well have been a misreading of "Pellon" an area of Halifax. In fact, in 1911 there was Walter Ackroyd, aged 29, born in Huddersfield, living in central Halifax. He was in what must have been a lodging house run by a Thomas Flanagan, a newsagent at 55 Woolshops. Over forty men as well as Flanagan’s family and servants were staying there.
Walter gave his occupation "Out Porter", to which the enumerator has added "Railway Co". This seems most likely to be the correct man: no other Walters were born in Huddersfield in the right period or resident anywhere local. Walter, it seems, was a railway worker.
We can be certain that Walter did not serve in 1914 or 15 and that he enlisted Huddersfield in the Duke of Wellington's Regiment, eventually serving in the Territorial, 2/4th Battalion. This suggests he did not wait to be called up, though we cannot be certain.
He died at the Battle of Cambrai in November 1917 and has no known grave but is remembered on the Memorial to the missing in Cambrai and at St. Philip's, Birchencliffe, though not on the original 1920 Roll of Honour but on the memorial in the churchyard.
The following extract is from Huddersfield's Roll of Honour: 1914-1922 (2014) by J. Margaret Stansfield: