I have several booklets on Gravesend airport. They were (still are?) available from the information centre 'Towncentric.'
Visit Gravesend, Gravesham for Kent Great Days Out & Family Fun
They are not mentioned on this page but as it says, not all are.
http://mediafiles.thedms.co.uk/Publi...0Products2.pdf
One is called 'Prelude to War' about aviation in Kent and has a few photos
and description of No 20 Elementary and Reserve Flying Training School.
There is another called Gravesend Airport 1939-1945 which has photos of that period. I also have another somewhere! of the pre war period.
These were published locally.
mmitch.