Hello Gig,
I double-checked on SDGW, because the Royal Berks service number did not look right and came up with this additional information:
Born: Headless Cross, Redditch
Enlisted: Birmingham
Resident: Webheath, Redditch
Died, France and Flanders, 7th Sept 1918
Formerly 3869; 2/1 Berkshire YeomanryThe service number 71417 certainly fits (1917 re-numbering).
2/1 Berks Yeo did not serve overseas and 1/1 were in Egypt 1917/18, prior to becoming a Machine Gun Corps unit.
Possibly Clifford was posted to 1/1 for a time

Phil