301738 Pte Barker-First Name ?

[albert1997]

CWGC shows this man's first name as Henry, but SDGW and his MIC shows it as John.

Is this an error somewhere ?

BARKER, HENRY
Rank:
Private
Service No:
301738
Date of Death:
23/04/1917
Regiment/Service:
Manchester Regiment
18th Bn.
Grave Reference
A. 13.
Cemetery
CUCKOO PASSAGE CEMETERY, HENINEL
Additional Information:
Brother of Mrs. E. Whalen, of 19, Brown St., Lily St., Harpurhey, Manchester.