I shot this Squirrel on the grass at Moorabbin Airport in mid 2009. The window in the floor behind the starboard front door is interesting. Presumably it was fitted out for a special purpose.
Andrew, a pilot who has flown this machine has since told me that: "the window on the pilot's side is a camera window, and there is also one on the floor next to the pilot seat for long-lining and filming." So now we know! Thanks, Andrew.