According this his first set of attestation papers dated December 1, 1914 at Toronto, Guilford Allain Slingsby was born on June 2, 1888 in Muneaton, Warwickshire, England. He listed his father Henry Slingsby, Muneaton, as his next of kin. He indicated that he was a farmer by trade and that he had had previous military experience with the "33rd C?S?". He was 26 years of age and stood 5 feet 5 inches tall. He had blue eyes, brown hair and a fair complexion.
His second set of attestation papers are dated April 8, 1915 at Toronto. He indicates that his father lives at Summerhill, Muneaton, Warkshire, England. He indicatd that he had 6 months previous miliary experience with the Warwickshire Light Infantry.