Simon.

You have managed to find that elusive connection, without doubt we have a case of an Air Gunner reacting to the loss of communication ability during combat and making a decision which saw him singularly becoming a pow. Thank you for your deductions and establishing the circumstances which had eluded me for such a long time. I find it interesting that the ORBs make no reference to him actually not being amongst the crew on the eventual return, just a simple one line entry in the summary. After such a long time I am inedited to you for your ability in solving this sticky matter for me.
Thank you very much....