Just a quickie then I really must go and do something else:
Fuji: I take your point entirely about Duxford displays: one should look for NOTAMS.
However there are numerous restoration/engineering setups there who at any time will shoot off and practice in the overhead.
Aerobatic practice takes place frequently in the days leading up to air displays and this is not notammed.
They really aren't keen for stuff going through their overhead so have an alternative planned.
I am sure the OP will read the Duxford entry in Pooleys (or others) where he will detect this feeling.
Cusco