Well, in almost every case of starter clicking I've had (not Mog), it's been a bad connection on the solenoid, but a dodgy battery connection could also do this. Make sure they are sound first.
Grinding from the aircon points to compressor bearings, but the compressor may load up something else driven by the same belt, so you need to look. If the power steering comes off the same belt drive, it's connected..... (no pun etc etc .....)
