Do you have your fathers Escape/Evasion Report or Liberation questionaire from the UK National Archives?
He may identify them in his report?
Whats your fathers name, he might be linked to them in a book or website?
is this him:
3323 2420 (-)
F/Sgt A C Kirk
75 Sqn Lancaster ND576
Lost on operation to Stuttgart July 44
http://www.conscript-heroes.com/MI9-05.html
This book is available on Google books,
Air Forces Escape & Evasion Society
Two Benjamins mentioned seem to be
Benjamin L O'Dell and Benjamin H St. John but neither page is in the free to view section!!