Thank you to all those who replied (and so quickly)

Unfortunately I don't have his marriage certificate. Dad was pretty sure Alfred 's place of birth was Plymouth, but as he was only 1 when his own Dad died, so this could easily be wrong.
His son William Alfred Gitsham (b 1911, d 1940) was a leading stoker on the HMS Acasta. I've seen the page on Alexander John Gitsham and also seen the memorial for the Scottish project showing all 3 of Alfred's sons that died in the war. None of this seems to give any more information on Alfred.
I do know that George was a jockey before he went away to war and he was presumed to be killed when the ship he was being held as a POW on was bombed. This information came from other people on other boats in the area. They were all told to go down below and when they came back up George's boat was missing.
I'll follow all of this information up. Please add anymore info if you find it.