From FreeBMD.org.uk (Transcripts of England & Wales BMD Indexes):
Birth, March qtr 1918
Fulham Registration District vol 1a, page 438
Hine, George F Mother's Maiden Name: Coe
And a possible marriage?
December qtr 1897
Fulham Registration District vol 1a, page 609
Hine, Richard James
Coe, Henrietta Ann
In my own tree, surnames used as middle names usually refer to a grandmother's maiden name?
So, I suspect that is what happened here.