km1971,
Interesting that you mention he was an early member. This is consistent with the background, which is as follows. He emigrated to Canada in 1908, where he met and married my grandmother in 1910. In May 1913, my grandmother sailed for Scotland with the two children (the younger dying on the voyage), my grandfather left for Scotland a few months later, and may have signed up before the outbreak of the war. My grandmother remained in Aberdeen with her mother for the duration of the war, and two more children, including my mother were born there. They all sailed for Canada in 1919.
I had always believed that the war was the reason they were all in the U.K. until a couple of years ago, when I found the passenger lists indicating they had left Canada in 1913. Now I don't know why they left. The other thing I had always believed was that he had been in the Canadian forces, not the British forces. Seeing my mother's birth record from Aberdeen corrected that.
Is there some way to find out the date he signed up?
Thanks very much for the information.