hiya TC.
i think chris is right,hes a territorial.
all the terriers were renumbered in 1917,with a six digit number,harry hasnt got one,which suggests he was invalided out of the army as medically unfit before 1917.
these ackroyds are the only servicemen listed in oldham[c1918]
ernest.56 herbert st,waterhead.
john.13 gartside st,clarksfield.
joseph.18 morley st,waterhead.
thomas.54 norbury st.clarksfield.
mack
ps,he was probably in the 1/10[oldham]battalion.