I hear a strange squeaking/squelling sound coming from somewhere around the alternator/water pump/fan belt, and the sound is only there when it is cold, drive it around and warm it up then it is gone, can someone suggest?

Should just be the fan belt. It might be getting a bit old and the rubber gets hard. Once you have run the car for a little while the belt warms up and becomes more flexible and so it stops squeeking.
You could spray some CRC onto the belt, this nomally stops the noise straight away