I am working my way through Jul-Sep 1944 ORB's for 106 Sqdn and noted a Lancaster on Ops with 9 crew aboard, it was flown by G/Capt WN McKechnie GC - he had a 2nd Pilot and 2nd Nav aboard. I haven't seen that before in a Main Force aircraft.
cheers PeteS
https://630squadron.wordpress.com/