Hello Claire
I sent you a post yesterday but I suspect it has gone astray. Trying again with this. I have been researching the Exalls for a friend for whom Albert Ernest Exall was a great-uncle. You are right about him (but wrong first name - not Alfred) and he was killed at Vimy Ridge while serving in the Canadian Army. I attach some useful information in jpg format for you. My friend's grandfather was the George Simeon Exall in the family tree attachment and she lives in South Wales.
Peter Hutchings Malvern Worcs