2008 Focus, Style trim... When the fan is on and the vent controls are set to windscreen, the air con comes on automatically, and when presumably the temperature is below a certain level the heated rear window does as well.

I would much prefer it if they stayed off, and came on when I wanted them to. Is there a way to disable these features??

You can use elm config for the heated screen, not sure about the aircon though. Have a look in the guides section for elm.

just have it offset from the windscreen by a click and the air con wont come on

Right, ta. I'd been offsetting the vent setting but sometimes it ends up at 12Oclock and then on comes the AC without you noticing. These things should be settable through the dash menu.

its a setting to demist your windscreen quicker but yeah it is a tad annoying

This is so annoying. I don't want aircon on when it's freezing cold and have just started my car or any other time when it's cold.

Like above set it to just off the window denmist icon with the control knobs to get around this.

The air con really does help demist the screen in the morning though.

Personally I like the option, the night before I set my blower to 3 and windscreen with the heat on. That way I just start the car, shut the door and open my gates, by the time I get back to it, the screens pretty much thawed out. Dab the wipers and I set off.

Horses for courses I guess, but like it has been posted, just tap the buttons to turn any if it off.