From the CAA
An ATZ at a civil aerodrome does not exist outside the notified hours of operation of the A/G, AFISO or ATC unit.
So if an airfield has published hours of 8am to 8pm but NOTAMs a closure between 1pm and 2pm can you land at a private site within the area of the ATZ without ATC permission (because there is no ATZ/ATC active)?
In my experience heli pilots have one opinion airport operations / ATC seem to have another. Opinions?
Regards, FB