There used to be an Air Gunners Association here in the UK, but I believe that it disbanded in the past year or so.
It might be worth making contact with the people at the Air Gunners room at the Yorkshire Air Museum, Elvington, Yorks. It is normally staffed by volunteers many of whom were Air Gunners during WW2 and who may be able to help guide you in the right direction.
Good luck
Linzee
PS: After initial posting found this page which details the history of the Air Gunners Association and confirms it was wound up in 2003.
http://www.tmquinn.net/airgunners/me...room/page2.htm