Might want to check with the Royal Aero Club in the UK to see if they have any records you could check, which may throw a bit more light on stuff. They are still very much in existence as the sporting aviation representative of the Federation Aeronautique International in the UK.
Believe it or not, they do still issue the 'Tickets' you read about when WW1 pilots got their licences - mine was number 100,875 when I got it in 1997, which I worked out puts me 96,980 after when
Edward Mannock got his ticket, which was 81 years prior to me getting mine!
Contact the Royal Aero Club here via email:
secretary@royalaeroclub.org
Al