Thought my alternator was going then gone. Atempted to charge the battery with no luck. Got my hands on another battery, started the car then disconnected the battery expecting the motor to cut out confirming an alternator problem. The engine continued to run but the air-con 'motor'(this amateur doesn't even know what it's called) was clunking rhythmically and the belt seemed to be slipping on the pulley. I hope that all makes sense. Just when I thought I had my head rapped around this I am suddenly out of my depth again.
Any help. ...hugely appreciated.

Go see an Auto Leccy.

A dead battery will stop the Alternator from Charging the Car. But you should never, every disconnect the battery from the car while its running.

The Battery provides a load for the Alternator to drive. Without it, the Voltage can Spike quite Wildly, and lots of bad things can happen. The electronics are designed to tolerate the posiblility, but its just not a good thing to do.

The AC kicking in and out is normal - as the AC Pump presurises the AC System correctly, the clutch disengages. When the pressure drops, the clutch re-engages. Hence the clunk etc.

Especially now, at the start of winter, Batteries start having sudden deaths. Even in QLD (who would have thought). The cold weather accelerates the death of one or more cells in your battery, meaning it wont hold enough charge, wont hold it for long, and appears that the alternator isnt working.

Nigel

Thanks Nigel, have been relying on the University of Google so not too surprised I got some dodgy info. Finally got my hands on a multi meter today. Battery is around 12.5 v and around 14 v when car is running. Was expecting 14.5-15v if alternator was functioning properly. Am I within an acceptable range do you think?

Thanks for the help
Mike

That sounds about right.

Nigel