"It has always been a bone of contention, exactly where the reading for a grid or Lat/Long reference is, for an Airfield/ Airstrip."
Does it really matter? If you are flying VFR you can see it out of the window. If you are flying a precision approach it will guide you to the runway. If you need a position to feed into the INS then a chart of airfield locations will tell you.
Is this another GPS users obsession?