Found the sections
alas haven’t got a heated screen in mine
Programmed Defrost Switch: Activates a program that automatically selects: inlet air to fresh air; distribution to screen only; blower to speed 5; rear screen heater on; windshield heater on (where fitted), A/C system to automatic mode. An amber LED in the switch is illuminated while the defrost program is active.
Economy Switch: Reduces the A/C compressor output to a minimum displacement condition x 5%, reducing the engine load required to operate the A/C compressor. An amber LED in the switch is illuminated when the economy mode is selected on.
also think the AC can’t be completely turned off, supposedly periodically runs to keep the seals from drying up , I think that’s how I read it