Thanks Sammy, that is exactly where I looked this morning and you are 100% correct.
When I dissembled it this morning I found is that the shaft with the little valve had come out of the electronics and the spring had lodged the taper tight into the hole in the plenum.
I managed to screw the little shaft back in but I don't know where it is supposed to sit exactly. I then put the IAC back on and the car now idle's, even from cold, and it is also not running as rich as it was.
Amazing when you solve the problem that everything suddenly fits.
As they say "hind sight is always the perfect science"
I will obviously purchase a new IAC but any recommendation on make? My problem is I'm in South Africa so it will have to be RockAuto or someone like that.