OK tested it out this morning, and I also recorded it. You can hear that annoying squeal in the video below at around 15-16 second mark, that instantly goes away and the revs ever so slightly change up or down I cannot tell which way...

I should also mention that this click or whatever has always happened not long after I started the car, but this time it also includes this squeal after wombat. It only happens when it's cold, so tomorrow morning I will put water or belt grip on it, to test what that does... But I suspect something else that engages or disengages. It can only be the alternator (clutch) or the fan ????